How Square is Your Square: A dial indicator method

On Jan 3, 7:21=A0pm, [email protected] wrote:
> On Thursday, January 3, 2013 6:57:37 PM UTC-5, -MIKE- wrote:
> > On 1/3/13 5:30 PM, [email protected] wrote:
>
> > > A minor caveat to this method is that it can be difficult to discern
>
> > > small gaps between the two pencil lines (especially with a thick
>
> > > pencil lead).
>
> > Use a knife.
>
> > > =A0The most you might be able to detect is a 0.010"
>
> > > difference which equates to a minimum detection of 0.036 degrees with
>
> > > an 8" square. Another caveat is that the edge you place your square
>
> > > against must be perfectly flat, otherwise you will not get an
>
> > > accurate calculation of your square's angle error.
>
> > > The dial indicator method is 10X more accurate.
>
> > Great, if we need to send a rocket into space, but not necessary for
>
> > woodworking. =A0:-)
>
> I like to have at least one master square that I know is balls to wall ac=
curate. =A0I had no way of checking before and I do now. =A0The Draw-A-Line=
and flip method will never tell you how far out of wack your square is - o=
nly that it might be out of wack. =A0There is no way to quantitate the angl=
e error unless you can measure the distance betwene the lines/knife marks w=
ith a caliper (good luck). =A0How much of a gap in between the marks is con=
sidered unacceptable? =A0You can't easily answer that question so why bothe=
r checking in the first place?

4x dollar store reading glasses.

In article <[email protected]>,
<[email protected]> wrote:

> Let me know what you guys think.
>
> I've been working on a new method (new?) for checking the squareness of a
> square using a dial indicator. The method works in theory. I've tried it
> and it seems to work in practice. A caveat is that the square needs a thick
> edge to support a stylus.
>
> I am going to work on a video demonstrating the process.
>
> http://www.garagewoodworks.com/square_a_square.php
>
> Thoughts?

Seems totally unnecessary. A pencil and a straight edge (a la sheet
good cutoff) is all you need to check if it's actually square. And it's
fast to set up.

--
Outside of a dog, a book is man's best friend. Inside a dog, it's too dark to
read. - Groucho Marx

In article <[email protected]>,
<[email protected]> wrote:

> read the article.

Did.

--
Outside of a dog, a book is man's best friend. Inside a dog, it's too dark to
read. - Groucho Marx

In article <[email protected]>, Swingman
<[email protected]> wrote:

> That said, you are only as accurate as your tools allow ...

Tools, and the material you are working. Context is a large part of it.

A couple of thousandths over two feet is out of context for woodworking
joints. The material is going to move more than that simply due to
weather variation.

I'd rather spend a few bucks on a quality square than putz around with
a dial indicator.

--
Outside of a dog, a book is man's best friend. Inside a dog, it's too dark to
read. - Groucho Marx

In article <[email protected]>,
<[email protected]> wrote:

> You're still left with not being able to quantitate the error. Are you
> following along?

I've watched you go from presenting what you thought was a good idea to
spending an inordinate amount of energy insulting anyone who disagrees
with you.

There's a solution for this at my end, fortunately. I am implementing
it now.

--
"You couldn't get a clue during the clue mating season in a field full
of horny clues if you smeared your body with clue musk and did the
clue mating dance." -- Edward Flaherty

On Thursday, January 3, 2013 9:05:34 PM UTC-5, Bill wrote:
> [email protected] wrote:
>=20
> > On Thursday, January 3, 2013 8:44:31 PM UTC-5, Bill wrote:
>=20
> >> I forgot to mention, what you have labeled as "References" are not
>=20
> >>
>=20
> >> references at all.
>=20
> >
>=20
> >
>=20
> > Yes they are. I am 'referring' to them in the article. It's done rout=
inely in the literature.
>=20
> References usally means bibliographical references (to related works).

Yes, usually. It is however, not incorrect how I used the term.


>=20
>=20
>=20
> "Notes" may be more appropriate (I'm not looking for an argument).

I like references. It's what I'm used to.


>=20
>=20
>=20
> Bill
>=20
>=20
>=20
>=20
>=20
> > See 5d below where as it applies here.
>=20
> >
>=20
> > ref=EF=BF=BDer=EF=BF=BDence (rfr-ns, rfrns)
>=20
> > n.
>=20
> > 1. An act of referring: filed away the article for future reference.
>=20
> > 2.
>=20
> > a. Significance in a specified context: Her speeches have special refer=
ence to environmental policy.
>=20
> > b. Meaning or denotation.
>=20
> > 3. The state of being related or referred: with reference to; in refere=
nce to.
>=20
> > 4. A mention of an occurrence or situation: made frequent references to=
her promotion.
>=20
> > 5.
>=20
> > a. A note in a publication referring the reader to another passage or s=
ource.
>=20
> > b. The passage or source so referred to.
>=20
> > c. A work frequently used as a source.
>=20
> > d. A mark or footnote used to direct a reader elsewhere for additional =
information.
>=20
> >
>=20
> >>
>=20
> >>
>=20
> >> Please re-do.
>=20
> >>
>=20
> >>
>=20
> >>
>=20
> >> Bill

On Friday, January 4, 2013 12:26:27 PM UTC-5, Scott Lurndal wrote:
> [email protected] writes:
>
>
>
>
>
> >I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)
>
> >
>
>
>
> I don't know why google groups double-spaces every one of your posts, but it is
>
> annoying.
>
>
>
> Starrett is in business to supply precision tools to the metalworking and patternmaking
>
> industries, for which a much higher level of precision is required than for building
>
> furniture, where "within a 32nd" is usually more than sufficient.

No. They are in business to sell their products to anyone that wants them. And I while I don't know the percentage, I am willing to bet that a significant percentage comes from woodworkers.

On 1/4/2013 5:52 PM, Doug Winterburn wrote:
> On 01/04/2013 02:09 PM, Mike Marlow wrote:
>> Leon wrote:
>>
>>> LOL... Is this why you never post any of your work? I don't find
>>> 32's of
>>> an inch tolerances acceptable in woodworking.

>> that, can we really advocate that such degrees of precision are genuinely
>> effective? I'm not talking about what we feel is effective - I'm
>> asking you
>> to provide real measured prrof of your claim.
>>
>
> I dunno - a 1/32" difference between the end shoulders and the long
> shoulders of a tenon on a M&T joint would definitely show, especially if
> the gap created was on the long shoulder side.

Absolutely correct!

BTW, here's that "measured proof", as requested above, that someone
should NOT "...find 32's of an inch tolerances acceptable in woodworking.":

https://picasaweb.google.com/111355467778981859077/EWoodShopJustStuff#5829750834071569842

:)

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
KarlCaillouet@ (the obvious)

On Thursday, January 3, 2013 8:44:31 PM UTC-5, Bill wrote:
> I forgot to mention, what you have labeled as "References" are not=20
>=20
> references at all.



Yes they are. I am 'referring' to them in the article. It's done routinel=
y in the literature. See 5d below where as it applies here.

ref=B7er=B7ence (rfr-ns, rfrns)
n.
1. An act of referring: filed away the article for future reference.
2.
a. Significance in a specified context: Her speeches have special reference=
to environmental policy.
b. Meaning or denotation.
3. The state of being related or referred: with reference to; in reference =
to.
4. A mention of an occurrence or situation: made frequent references to her=
promotion.
5.
a. A note in a publication referring the reader to another passage or sourc=
e.
b. The passage or source so referred to.
c. A work frequently used as a source.
d. A mark or footnote used to direct a reader elsewhere for additional info=
rmation.

>=20
>=20
>=20
> Please re-do.
>=20
>=20
>=20
> Bill

On Friday, January 4, 2013 12:43:52 AM UTC-5, Bill wrote:
> [email protected] wrote:
>
> > On Thursday, January 3, 2013 10:01:36 PM UTC-5, Doug Miller wrote:
>
> >>> Where are you having trouble with the math?
>
> >>
>
> >>
>
> >> Ummm.... Brian, you don't know Bill personally. I do.
>
> >>
>
> >>
>
> >>
>
> >> He's not the sort of guy to toot his own horn, so without his consent, I'm not going to say why I'm
>
> >>
>
> >> so sure of it, but please trust me on this: the man *knows* math.
>
> > Good. The math is sound. Let's see something from Bill to the contrary.
>
> >
>
> > I've checked it and rechecked it.
>
>
>
> Doug, Thank you for your support. Brian, Thank you for your indulgence,
>
> as I came into
>
> this confused about the details of the procedure/algorithm that was
>
> being proposed--and I apologize for any
>
> fuss that I may have created as a result of that. I think I may need to
>
> see a picture with a real dial
>
> indicator in it, or a drawing of one, to understand the procedure. There
>
> is so sense in me making any further comments, other than the
>
> request for clarification I have already made, until I understand the
>
> algorithm.


I added a new Figure that might help:
http://www.garagewoodworks.com/pictures/unsquare_mitergauge_isos_small.jpg

see:
http://www.garagewoodworks.com/square_a_square.php


>
>
>
> Brian, I know Doug well-enough to know that he has a lot to offer on
>
> this problem. If he understands what you are trying to do, than
>
> I'm sure that he can help you make it "first-rate" if that's your goal.
>
> We're all here to help and support each other, right?
>
>
>
> Cheers,
>
> Bill

On Thursday, January 3, 2013 10:05:16 PM UTC-5, Gordon Shumway wrote:
> On Thu, 3 Jan 2013 13:58:44 -0800 (PST), [email protected]
>
> wrote:
>
>
>
> >Let me know what you guys think.
>
> >
>
> >I've been working on a new method (new?) for checking the squareness of a square using a dial indicator. The method works in theory. I've tried it and it seems to work in practice. A caveat is that the square needs a thick edge to support a stylus.
>
> >
>
> >I am going to work on a video demonstrating the process.
>
> >
>
> >http://www.garagewoodworks.com/square_a_square.php
>
> >
>
> >Thoughts?
>
>
>
> Are you off your meds again?

Too complex for you I know. I'll dumb it down for you next time.

On Thursday, January 3, 2013 8:41:23 PM UTC-5, Larry W wrote:
> In article <[email protected]>,
>=20
> <[email protected]> wrote:
>=20
> >On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:
>=20
> >> In article <[email protected]>,
>=20
> >> <[email protected]> wrote:
>=20
> >> > Let me know what you guys think.
>=20
> >> > I've been working on a new method (new?) for checking the squareness=
of a
>=20
> >> > square using a dial indicator. The method works in theory. I've tr=
ied it
>=20
> >> > and it seems to work in practice. A caveat is that the square needs=
a thick
>=20
> >> > edge to support a stylus.
>=20
> >> > I am going to work on a video demonstrating the process.
>=20
> >> > http://www.garagewoodworks.com/square_a_square.php
>=20
> >> > Thoughts?
>=20
> >> Seems totally unnecessary. A pencil and a straight edge (a la sheet
>=20
> >> good cutoff) is all you need to check if it's actually square. And it'=
s
>=20
> >> fast to set up.
>=20
> >read the article.
>=20
> > A minor caveat to this method is that it can be difficult to discern
>=20
> >small gaps between the two pencil lines (especially with a thick pencil
>=20
> >lead). The most you might be able to detect is a 0.010" difference which
>=20
> >equates to a minimum detection of 0.036 degrees with an 8" square.
>=20
> > Another caveat is that the edge you place your square against must
>=20
> >be perfectly flat, otherwise you will not get an accurate calculation of
>=20
> >your square's angle error.
>=20
> >The dial indicator method is 10X more accurate.
>=20
>=20
>=20
> What are we building here, bookcases or space shuttles? 10X more accurate
>=20
> is not necessary for woodworking.


Scenario: You make it out to the woodshop after a hard night of drinking. =
As the acetaldehyde takes it's effect on you, you drop your Starrett square=
on the concrete floor. What do you do? Continue to use it and hope for t=
he best or check to see if it's still of 'Starrett Quality'? How do you ch=
eck?


>=20
>=20
>=20
>=20
>=20
> --=20
>=20
> Make it as simple as possible, but not simpler. (Albert Einstein)
>=20
>=20
>=20
> Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On Jan 3, 11:02=A0pm, [email protected] wrote:
> On Thursday, January 3, 2013 10:55:23 PM UTC-5, Doug Miller wrote:
> > [email protected] wrote in
>
> >news:[email protected]:
>
> > > On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller
>
> > > wrote:
>
> > >> [email protected] wrote in
>
> > >> news:ee116537-b047-4754-88e2-dfc87af63570
>
> > >> @googlegroups.com:
>
> > >> > On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam
>
> > >> > wrote:
>
> > >> >> Then use a marking knife.
>
> > >> > You're still left with not being able to quantitate the
>
> > >> > error. =A0Are you following along?
>
> > >> _Of course_ you can "quantitate" [sic] the error. What makes
>
> > >> you think it can't be measured?
>
> > > Measure thousands of an inch between two lines. =A0Sure it can be
>
> > > measured. =A0Accurately? =A0No.
>
> > What makes you think that? Do you own a set of feeler gauges?
>
> I have never needed feeler gauges. =A0They work on a very basic principle=
and I feel confident making that claim.

3 x 5 index card =3D 0.004.
Playing card =3D 0.012".
Beer can stock =3D 0.015".
Rolling paper (Job brand) =3D 0.001".
and so on...

On Thursday, January 3, 2013 7:41:36 PM UTC-5, dpb wrote:
> On 1/3/2013 6:21 PM, [email protected] wrote:
>
> ...
>
>
>
> > I like to have at least one master square that I know is balls to
>
> > wall accurate. I had no way of checking before and I do now. The
>
> > Draw-A-Line and flip method will never tell you how far out of wack
>
> > your square is - only that it might be out of wack. There is no way
>
> > to quantitate theangle error ...
>
>
>
> What difference does it make what the numeric value is?
>
>
>
> If it's enough to detect that way, it's enough that for really precise
>
> layouts it's off.
>
>
>
> So, what you gonna' do at that point, anyway even if you do know
>
> _precisely_ how much that is?

If you don't know how much it's off you can't make a call either way.

So why bother checking?


> Eggs-ackly the same thing as if you only
>
> know it's off---either ignore it and go on, go get a new Starrett, or
>
> adjust it until it does pass (the peen method works a charm for that).
>
>
>
> If it passes the pencil test, it's plenty close enough for woodworking;

What is a "pass" on the pencil test?

>
> even fine woodworking. The wood itself moves more than that.
>
>
>
> --

On Thursday, January 3, 2013 7:40:30 PM UTC-5, Bill wrote:
> Bill wrote:
>
> > [email protected] wrote:
>
> >> Let me know what you guys think.
>
> >>
>
> >> I've been working on a new method (new?) for checking the squareness
>
> >> of a square using a dial indicator. The method works in theory.
>
> >> I've tried it and it seems to work in practice. A caveat is that the
>
> >> square needs a thick edge to support a stylus.
>
> >>
>
> >> I am going to work on a video demonstrating the process.
>
> >>
>
> >> http://www.garagewoodworks.com/square_a_square.php
>
> >>
>
> >> Thoughts?
>
> >
>
> > Sinced/dx (arctan) is close to 1 near 0, yourerror is not very big,
>
>
>
> I appreciate the point that you are trying to make, but I don't find the
>
> argument given to be as rigorous as it should be.
>
>
>
> I'd enjoy seeing a re-write. I'll help here if you like. I don't think
>
> that L was "well-defined" (consistent) in the present argument
>
> Bill
>
>
>
>
>
> > but your equation which divides an angle by L (before applying arctan)
>
> > doesn't make sense. For instance, it suggests that if you choose L
>
> > great enough that your error will be as small as you need it to be. I
>
> > did not try to redo your derivations, but I am willing to do so if we
>
> > don't find a concensus. By the way,you might sketch a triangle
>
> > somewhere(tan = opp/adj)for those that may be a bit rusty at doing trig.
>
> >
>
> > Bill

L is the length of the square's edge. It was defined adequately.

On 1/4/2013 12:06 PM, -MIKE- wrote:
> So if you're square is off by 1/10 the width of an atom, you're not very
> good. :-P

LOL ... it depends upon which atom. You never know when working with
planks when the Planck constant might come in handy. :)


--
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Wood Shop: www.e-WoodShop.net
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KarlCaillouet@ (the obvious)

On 1/4/2013 12:16 PM, Phil Kangas wrote:
> "Swingman" <[email protected]> wrote in message
>> On 1/4/2013 11:22 AM, [email protected]
>> wrote:
>>
>>> For some reason it is almost impossible to
>>> introduce/discuss a method that mentions the
>>> word "accuracy" without the knuckleheads
>>> screaming the tired NASA quip.
>>
>> Accuracy is a "detail" in the process.
>>
>> "The devil is in the details".
>>
>> "Attention to detail is the difference between
>> mediocrity and supremacy."
>>
>> Both arguably why some succeed, some don't ...
>> in war, woodworking, or otherwise. :)
>
> Like, measure it with a micrometer, mark it off
> with a tape
> measure and felt tip pen, then cut it off with a
> chain saw! ;>)}

More like "measure twice, cut once, pound to fit". ;)

--
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Wood Shop: www.e-WoodShop.net
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KarlCaillouet@ (the obvious)

On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in news:214a7bab-b962-477d-8340-
>
> [email protected]:
>
>
>
> > Scenario: You make it out to the woodshop after a hard night of drinking. As the
>
> > acetaldehyde takes it's effect on you, you drop your Starrett square on the concrete floor.
>
>
>
> Doesn't happen in my shop. That's a hard and fast safety rule here: if I drink, I stay out of the
>
> shop until after a full night's sleep.
>
>
>
> That doesn't mean I can't or won't ever drop the square, of course -- just means that if I do, it
>
> will be the result of my own innate clumsiness, not of inebriation.
>
>
>
> > What do you do? Continue to use it and hope for the best or check to see if it's still of
>
> > 'Starrett Quality'? How do you check?
>
>
>
> Your imagination is lacking, Brian <g>. I can think of at least half a dozen things I could
>
> check it against:
>
> -- angle between the jointer fence and bed (previously set using the same Starrett square)

How can you be sure it's still square to the level of accuracy required?


>
> -- angle between the fence of the Incra 3000 miter gauge, and the miter bar (ditto)

ibid

>
> -- angle between the Incra 3000 and the table saw blade (ditto)

ibid

>
> -- one of my Jevons 3D squares <http://www.jevonstoolco.com/> -- I have no connection
>
> with the company, except as a *totally* satisfied customer -- these are great products, and
>
> as close to dead-on-perfect as a woodworking tool needs to be (within 0.002" in 6",
>
> according to the manufacturer)
>
> -- my crosscut sled

ibid

>
> -- any corner of at least seven pieces of furniture in my home that I've made using some or

I hope you're joking.

>
> all of the above

On Thursday, January 3, 2013 10:53:50 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in news:bccdd6ea-eb29-401f-8b92-b76c1cb38818
>
> @googlegroups.com:
>
>
>
> > That's not how the math is done.
>
>
>
> LMAO

See my other post. I misplaced a decimal. Happens sometimes.

>
> >
>
> > If your gap between the two lines (drawn from the same point) is 0.016" then half the
>
> distance is 0.008" which is your "Opposite Side". Now I understand the confusion here.
>
> >
>
> > See:
>
> > http://www.garagewoodworks.com/angle_math.php?adjacent=8&opposite=0.008&angle=
>
> >
>
> > Your Opposite side is 0.008". The Adjacent side is 8".
>
>
>
> And tangent = opposite / adjacent = 0.008 / 8 = 0.001.
>
>
>
> (As I noted previously, the 8" is actually the hypotenuse, not the adjacent side, but for
>
> angles this small, it doesn't matter.)
>
>
>
> Anyway... arctan (0.001) IS NOT 0.5 degrees. You're off by an order of magnitude.
>
> [...]
>
> >> > What is your limit of detection for measuring gaps between
>
> >> > lines? I hope it's less than 0.016", but I can understand if
>
> >> > it's not.
>
> >>
>
> >> I can estimate much finer gaps than that by eye.
>
> >
>
> > And I once caught a fish ------This Big------.
>
>
>
> If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without


I can discern a difference. But i wouldn't be able to quantitate the two gaps to the level of accuracy required. And neither can you.

>
> using precision equipment, then you need to visit an optometrist. Seriously.

On Thursday, January 3, 2013 8:55:20 PM UTC-5, Larry W wrote:
> In article <[email protected]>,
>
> <[email protected]> wrote:
>
> >On Thursday, January 3, 2013 8:41:23 PM UTC-5, Larry W wrote:
>
> >> What are we building here, bookcases or space shuttles? 10X more accurate
>
> >> is not necessary for woodworking.
>
> >
>
> >Scenario: You make it out to the woodshop after a hard night of
>
> >drinking. As the acetaldehyde takes it's effect on you, you drop your
>
> >Starrett square on the concrete floor. What do you do? Continue to use
>
> >it and hope for the best or check to see if it's still of 'Starrett
>
> >Quality'? How do you check?
>
> >
>
>
>
> I'm by no means a teetotaler, but I haven't had a "hard night of drinking"
>
> in over 20 years. And if or when I did, I sure wouldn't head to the wood
>
> shop afterwards. And if I did, I probably wouldn't use one of my Starret
>
> squares. And if I did use the Starret, probaly wouldn't drop it. And if
>
> I did happen to drop it, after a hard night of drinking, I probably
>
> wouldn't care enough to check it.

Then why did you buy a Starret? :)


>
>
>
> What was the question again?
>
>
>
>
>
>
>
> --
>
> Make it as simple as possible, but not simpler. (Albert Einstein)
>
>
>
> Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org

On 1/3/2013 7:32 PM, [email protected] wrote:
> On Thursday, January 3, 2013 8:30:56 PM UTC-5, [email protected] wrote:
>> I challenge anyone to find a flow in my math. :)
>>
>>
>>
>> Good luck.
>
> Flaw Not flow. /that was intentional (grin)/

Appears to be a matter of resolution. I'm of the camp that if you don't
have perfection as a goal for every step of the process, you will never
scratch that itch some of us are cursed with.

At the same time, I'm just as guilty as anyone of occasionally settling
for less ... mainly due to time, circumstances, the medium
(woodworking), and the need to 'git r' done'. ;)

That said, you are only as accurate as your tools allow ...

--
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Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
KarlCaillouet@ (the obvious)

On 1/4/2013 5:26 PM, Bill wrote:
> Leon wrote:
>> On 1/4/2013 3:09 PM, Mike Marlow wrote:
>>> Leon wrote:
>>>
>>>> LOL... Is this why you never post any of your work? I don't find
>>>> 32's of
>>>> an inch tolerances acceptable in woodworking. If you want
>>>> multiple width and length pieces to fit precisely within a given
>>>> constraint you have to do a lot better than 32's. A whole lot better.
>>>
>>> Yer killin' me here brother! How much better can you really get? How
>>> much
>>> better realy results in a difference in the work that you are doing I
>>> understand that you may pursue a more difinitive precisions, but what
>>> I am
>>> asking is can you definitively define the benefit to that? So - if
>>> we are
>>> dealing with machinery and tools, and techinques that are less
>>> precise than
>>> that, can we really advocate that such degrees of precision are
>>> genuinely
>>> effective? I'm not talking about what we feel is effective - I'm
>>> asking you
>>> to provide real measured prrof of your claim.
>>>
>>
>>
>> Simply think, no gap in a joint. That is a tolerance much less than
>> 1/32".
>>
>> Take a face frame that has two rows of drawers. 2 outer stiles, 1
>> center stile. Between the stiles are rails that separate the stack of
>> drawers in each row. Top and bottom rails are a total length of the
>> drawer rails on each side and the center stile combined. The outer
>> stiles are set apart a specific distance.
>>
>> If all of your stiles are not a precise width and your rails are not a
>> complimentary precise width you get a gap in the joints.
>
> I think I would cut the top and bottom rails (and top and bottom stiles)
> to size after fitting the rest, no???

I made the description a bit confusing with width of rails. That should
have been length of rails. Basically you have 2 different length rails
between the outer rails with a center stile separating the drawer
divider rails. It is easy enough to cut the upper and bottom rails to a
given length but what length do you cut the drawer divider rails? The
answer would be the length of the upper or bottom rail less the width of
the center stile divided by two. If the stiles are off in width by
x/64" the drawer divider rails have to be cut accordingly.

You use measuring techniques far more accurate than a rule with 64th"
markings.





>
> BTW, I enjoyed the video on "accuracy in woodworking" and intend to
> watch it again (and practice).
>
> Bill
>

On Thursday, January 3, 2013 8:43:05 PM UTC-5, Bill wrote:
> [email protected] wrote:
>
>
>
> > There is no need to "try again"
>
>
>
> Then who is being arrogant?
>
>
>
> and I appreciate your veiled
>
> > arrogance.
>
>
>
>
>
> > Where are you having trouble with the math?
>
>
>
> Your identifiers are poorly chosen making your "work" difficult to read.

>
> From your words/diagram, it looks like delta1, delta2, and L are all
>
> the same.

Not at all. The red d2 is above the red line. d denotes distance.

The passage "take a reading at the bottom of the square (d2 in Figure 1)" should have clued you in that d was a distance. We are, after all, discussing a dial indicator method. Dial indicators measure distances.

>
> I don't see the 5-degrees you mentioned (in your diagram).

" Tilt your miter gauge to approximately 5 degrees." You can't tell that the miter gauge and square are tilted in Figure 1?

>
>
>
> Doing math is like doing design: Do-over, and do-over, and do-over. One
>
> should
>
> get quite humble about the process!

Point out what you think needs a do over. If you have other questions let me know.


>
>
>
> Bill

On Thursday, January 3, 2013 10:01:36 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in news:5443d0e1-47e2-4bf4-9dc6-237d07bf6357
>
> @googlegroups.com:
>
>
>
> > There is no need to "try again" and I appreciate your veiled arrogance.
>
> >
>
> > Where are you having trouble with the math?
>
>
>
> Ummm.... Brian, you don't know Bill personally. I do.
>
>
>
> He's not the sort of guy to toot his own horn, so without his consent, I'm not going to say why I'm
>
> so sure of it, but please trust me on this: the man *knows* math.

Good. The math is sound. Let's see something from Bill to the contrary.

I've checked it and rechecked it.

On Jan 4, 6:52=A0pm, Doug Winterburn <[email protected]> wrote:
> On 01/04/2013 02:09 PM, Mike Marlow wrote:
>
>
>
>
>
>
>
>
>
> > Leon wrote:
>
> >> LOL... Is this why you never post any of your work? =A0I don't =A0find=
32's of
> >> an inch tolerances acceptable in woodworking. =A0If you want
> >> multiple width and length pieces to fit precisely within a given
> >> constraint you have to do a lot better than 32's. =A0A whole lot bette=
r.
>
> > Yer killin' me here brother! =A0How much better can you really get? =A0=
How much
> > better realy results in a difference in the work that you are doing =A0=
I
> > understand that you may pursue a more difinitive precisions, but what I=
am
> > asking is can you definitively define the benefit to that? =A0So - if w=
e are
> > dealing with machinery and tools, and techinques that are less precise =
than
> > that, can we really advocate that such degrees of precision are genuine=
ly
> > effective? =A0I'm not talking about what we feel is effective - I'm ask=
ing you
> > to provide real measured prrof of your claim.
>
> I dunno - a 1/32" difference between the end shoulders and the long
> shoulders of a tenon on a M&T joint would definitely show, especially if
> the gap created was on the long shoulder side.

I suppose you could cheat by cutting the other
3 shoulders short....

<[email protected]> wrote:

> Let me know what you guys think.
-----------------------------------------------------------
A slow night in the Carolinas.

Lew

I wrote:

> A slow night in the Carolinas.
---------------------------------------------

<[email protected]> wrote:


> Then go out and get a drink Lew! Get off yer butt! :)
------------------------------------------------------
You must be kidding, it's 50F and dropping tonight.

Time to throw another log on the fire and enjoy
a toddy.

Lew

<[email protected]> wrote:
>
> Man I wish we had a log fireplace. The fake gas log variety just
> doesn't cut it.
------------------------------------------------------------------
You can forget a log fireplace in SoCal.

The South Coast Air Quality District outlawed open log fire burning
fire places years ago as an air pollution source problem.

Lew

"Doug Miller" wrote:

> Some years ago, I formulated these rules of thumb. If a piece of any
> significant size is out of
> square, level, or plumb by...
>
> 1 part in 100 -- *immediately obvious* to a casual observer (don't
> believe me? get a level
> and check, the next time it's immediately obvious that a picture on
> your wall doesn't hang
> straight)
>
> 1 part in 200 -- apparent to anyone who is looking for flaws
>
> 1 part in 400 -- won't be seen, but can be readily found with common
> carpentry tools (level,
> tape measure, etc)
>
> 1 part in 800 -- can't be found without precision measuring tools
>
> The significance of these rules is that the accuracy of your work
> won't be any better than the
> accuracy of the tools you produce it with (e.g. you can't get 1 part
> in 800 results with a
> "square" that measures 89.7 degrees).
----------------------------------------------------------------
Many on this list may not be old enough to remember the most useful
of all formulas:

"If a Flying Red Horse can't spot the difference from a thousand feet,
you're good to go".

Lew

"Swingman" wrote:

> More like "measure twice, cut once, pound to fit". ;)
-----------------------------------------
Always listed as a detail note on an assembly drawing as follows:

"Hammer and file to fit".

Lew

On 01/04/2013 02:09 PM, Mike Marlow wrote:
> Leon wrote:
>
>> LOL... Is this why you never post any of your work? I don't find 32's of
>> an inch tolerances acceptable in woodworking. If you want
>> multiple width and length pieces to fit precisely within a given
>> constraint you have to do a lot better than 32's. A whole lot better.
>
> Yer killin' me here brother! How much better can you really get? How much
> better realy results in a difference in the work that you are doing I
> understand that you may pursue a more difinitive precisions, but what I am
> asking is can you definitively define the benefit to that? So - if we are
> dealing with machinery and tools, and techinques that are less precise than
> that, can we really advocate that such degrees of precision are genuinely
> effective? I'm not talking about what we feel is effective - I'm asking you
> to provide real measured prrof of your claim.
>

I dunno - a 1/32" difference between the end shoulders and the long
shoulders of a tenon on a M&T joint would definitely show, especially if
the gap created was on the long shoulder side.


--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
-Winston Churchill

On 01/05/2013 07:10 AM, Doug Miller wrote:
> "CW" <[email protected]> wrote in
> news:[email protected]:
>
>>
>>
>> "Mike Marlow" wrote in message news:[email protected]...
>>
>> Yer killin' me here brother! How much better can you really get? How much
>> better realy results in a difference in the work that you are doing I
>> understand that you may pursue a more difinitive precisions, but what I am
>> asking is can you definitively define the benefit to that? So - if we are
>> dealing with machinery and tools, and techinques that are less precise than
>> that, can we really advocate that such degrees of precision are genuinely
>> effective? I'm not talking about what we feel is effective - I'm asking you
>> to provide real measured prrof of your claim
>> ======================================================================
>> Go out and make a mortise and tennon joint with the tennon 1/32 to big.
>
> That's an easier problem to fix than making them 1/32" too small... ;-)
>
BTDT - glue on some thin stock to the tenon cheeks and re-cut.


--
"Socialism is a philosophy of failure,the creed of ignorance, and the
gospel of envy, its inherent virtue is the equal sharing of misery"
-Winston Churchill

On Thursday, January 3, 2013 8:04:12 PM UTC-5, Bill wrote:
> [email protected] wrote:
>=20
> > On Thursday, January 3, 2013 7:24:24 PM UTC-5, Bill wrote:
>=20
> >> [email protected] wrote:
>=20
> >>
>=20
> >>> Let me know what you guys think.
>=20
> >>> I've been working on a new method (new?) for checking the squareness =
of a square using a dial indicator. The method works in theory. I've trie=
d it and it seems to work in practice. A caveat is that the square needs a=
thick edge to support a stylus.
>=20
> >>> I am going to work on a video demonstrating the process.
>=20
> >>> http://www.garagewoodworks.com/square_a_square.php
>=20
> >>> Thoughts?
>=20
> >>
>=20
> >>
>=20
> >> Sinced/dx (arctan) is close to 1 near 0, yourerror is not very big, bu=
t
>=20
> >>
>=20
> >> your equation which divides an angle by L (before applying arctan)
>=20
> >>
>=20
> >> doesn't make sense. For instance, it suggests that if you choose L
>=20
> >>
>=20
> >> great enough that your error will be as small as you need it to be. I
>=20
> >>
>=20
> >> did not try to redo your derivations, but I am willing to do so if we
>=20
> >>
>=20
> >> don't find a concensus. By the way,you might sketch a triangle
>=20
> >>
>=20
> >> somewhere(tan =3D opp/adj)for those that may be a bit rusty at doing t=
rig.
>=20
> >>
>=20
> >>
>=20
> >>
>=20
> >> Bill
>=20
> > Trust me, the math works.
>=20
> If you are going to present the math, then do so (properly).
>=20
>=20
>=20
> The sentence tht you wrote: "The answer given will be the amount in=20
>=20
> degrees that your square is off. "
>=20
> is terrible. Squares are not "off", degrees are not measure in amounts,=
=20

>=20
> and no answer was given (and no question was asked)!!

Squares can be "off" in the sense that they are not a true 90 degrees. Eve=
ry square will be "off" to some degree. Perfection is imaginary. :)


>=20
>=20
>=20
> If you are going to get rigorous, then do so--let's not pawn it off.=20

Reposted for your convenience:
"For the same angle error, as L get longer so does abs(Delta1 - Delta2). "

>=20
> "Trust Me, the math works", should not follow your (lack of a) a=20
>=20
> successful derivation.
>=20
> Lets not trip to slip the argument by people just because you figure=20
>=20
> you've already worked hard enough on it! I enjoy well-done mathematics=
=20
>=20
> as much as anybody, surely more than some. Hope to see you try again.

There is no need to "try again" and I appreciate your veiled arrogance.

Where are you having trouble with the math?

>=20
>=20
>=20
> Bill
>=20
>=20
>=20
>=20
>=20
> > Draw a few squares that are off by a little in CAD and check.
>=20
> >
>=20
> > Use my online calculator:
>=20
> > http://www.garagewoodworks.com/square_a_square_Math.php

I challenge anyone to find a flow in my math. :)

Good luck.

On Friday, January 4, 2013 12:43:52 AM UTC-5, Bill wrote:
> [email protected] wrote:
>=20
> > On Thursday, January 3, 2013 10:01:36 PM UTC-5, Doug Miller wrote:
>=20
> >>> Where are you having trouble with the math?
>=20
> >>
>=20
> >>
>=20
> >> Ummm.... Brian, you don't know Bill personally. I do.
>=20
> >>
>=20
> >>
>=20
> >>
>=20
> >> He's not the sort of guy to toot his own horn, so without his consent,=
I'm not going to say why I'm
>=20
> >>
>=20
> >> so sure of it, but please trust me on this: the man *knows* math.
>=20
> > Good. The math is sound. Let's see something from Bill to the contrar=
y.
>=20
> >
>=20
> > I've checked it and rechecked it.
>=20
>=20
>=20
> Doug, Thank you for your support. Brian, Thank you for your indulgence,=
=20
>=20
> as I came into
>=20
> this confused about the details of the procedure/algorithm that was=20
>=20
> being proposed--and I apologize for any
>=20
> fuss that I may have created as a result of that. I think I may need to=
=20
>=20
> see a picture with a real dial
>=20
> indicator in it, or a drawing of one, to understand the procedure. There=
=20
>=20
> is so sense in me making any further comments, other than the
>=20
> request for clarification I have already made, until I understand the=20
>=20
> algorithm.
>=20
>=20
>=20
> Brian, I know Doug well-enough to know that he has a lot to offer on=20
>=20
> this problem. If he understands what you are trying to do, than
>=20
> I'm sure that he can help you make it "first-rate" if that's your goal.=
=20
>=20
> We're all here to help and support each other, right?



The procedure really couldn't be any simpler, I can only conclude that you =
have not read the procedure carefully enough.
Procedure: As shown in Figure 1, position the dial indicator to the left o=
f the square and miter gauge so that the stylus makes contact with the squa=
re to obtain reference distance d1. Push the square and miter gauge forwar=
d to obtain distance d2. If you zeroed the dial indicator at d1 then the D=
elta1 is determined directly (See equation 1). Flip the square over and re=
peat the same process with the dial indicator on the right side to obtain D=
elta2. Delta2 =3D abs(d3-d4).
L is the length of the square. Because we rotated the square and miter gau=
ge (to make the calculations work) there will be some error introduced into=
the equation that is very small. See Reference 2. L actually gets a litt=
le smaller because of the rotation.
If you have access to CAD, draw an 8" square with an angle of 89.5 degrees =
(0.5 degree angle error). Create an isosceles trapezium to simulate the tw=
o squares coming together when flipped. =20

http://upload.wikimedia.org/wikipedia/commons/b/b7/Isosceles_trapezoid.jpg

(With the 0.5 degree angle error, Figure1 creates an isosceles trapezoid)
Rotate your trapezoid by 5 degrees to give a representation of Figure 1 in =
CAD. Measure your d1 - d4 and calculate the angle error per equation 2. Y=
ou should calculate an angle error of 0.498 degrees. The 0.002 degrees tha=
t the calculation is off is explained in reference 2.
I hope this helps.



>=20
>=20
> Cheers,
>=20
> Bill

On Thu, 03 Jan 2013 19:09:31 -0600, -MIKE- <[email protected]>
wrote:



>>
>
>Again, we're back to my original point. We're talking woodworking. How
>exact does a 2' square need to be?

If I can't see it in the finished product, it is close enough. If a
bookcase does not rack and fall down, it is square enough.

On Thursday, January 3, 2013 8:09:31 PM UTC-5, -MIKE- wrote:
> On 1/3/13 6:51 PM, [email protected] wrote:
>
> > On Thursday, January 3, 2013 7:46:14 PM UTC-5, -MIKE- wrote:
>
> >> On 1/3/13 6:40 PM, [email protected] wrote:
>
> >>
>
> >>
>
> >>>> Yeah, ok man... good luck with those rocket ships. :-)
>
> >>
>
> >>
>
> >>> Instead of being a fucking smart ass why don't you try answering my questions? :)
>
> >>
>
> >>
>
> >> Touchy, touchy. Why do you need to know how far out it is?
>
> >
>
> > How do you know when to throw away the square? Where do you draw the line (pun intended)?
>
> >
>
>
>
> Again, we're back to my original point. We're talking woodworking. How
>
> exact does a 2' square need to be? In my mind, within the width of the
>
> edge of an exact blade over 2' is plenty close.

When is it not close? Two blade widths? Three? And why?

>Using the mark and flip
>
> method is plenty good enough. If a person doesn't have a factory edged,
>
> 2'x4' piece of plywood or mdf at his disposal somewhere, he probably
>
> shouldn't be woodworking. An aluminum straight edge clamped to a work
>
> bench does fine in that regard, as well. Something a woodworking
>
> shouldn't be without, either.
>
>
>
>
>
> >> Do you have
>
> >> an adjustment method that you dial in an amount and it corrects that much?
>
> >
>
> > No. But I'll know what contributed to my joints not being square.
>
> >
>
>
>
> I can use the mark and flip method to know if my square contributed to
>
> my out of square joints.

Again. By what means does the flip method tell you to drop the square in the trash? And why?


>That is, unless I'm trusting my square to set
>
> my edge guide for ripping a 30' piece of plywood. :-)
>
>
>
>
>
> --
>
>
>
> -MIKE-
>
>
>
> "Playing is not something I do at night, it's my function in life"
>
> --Elvin Jones (1927-2004)
>
> --
>
> http://mikedrums.com
>
> [email protected]
>
> ---remove "DOT" ^^^^ to reply

On Thursday, January 3, 2013 10:43:22 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in
>
> news:[email protected]:
>
>
>
> > On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller
>
> > wrote:
>
> >> [email protected] wrote in
>
> >> news:214a7bab-b962-477d-8340-
>
> >>
>
> >> [email protected]:
>
> >>
>
> >>
>
> >>
>
> >> > Scenario: You make it out to the woodshop after a hard night
>
> >> > of drinking. As the acetaldehyde takes it's effect on you,
>
> >> > you drop your Starrett square on the concrete floor.
>
> >>
>
> >>
>
> >>
>
> >> Doesn't happen in my shop. That's a hard and fast safety rule
>
> >> here: if I drink, I stay out of the shop until after a full
>
> >> night's sleep.
>
> >>
>
> >> That doesn't mean I can't or won't ever drop the square, of
>
> >> course -- just means that if I do, it will be the result of my
>
> >> own innate clumsiness, not of inebriation.
>
> >>
>
> >> > What do you do? Continue to use it and hope for the best or
>
> >> > check to see if it's still of
>
> >> > 'Starrett Quality'? How do you check?
>
> >>
>
> >> Your imagination is lacking, Brian <g>. I can think of at least
>
> >> half a dozen things I could check it against:
>
> >>
>
> >> -- angle between the jointer fence and bed (previously set
>
> >> using the same Starrett square)
>
> >
>
> > How can you be sure it's still square to the level of accuracy
>
> > required?
>
>
>
> I check it periodically, using both the Starrett and the Jevons
>
> squares. Don't you?

I periodically check my jointer fence with a dial indicator (Powermatic) and it's always off by +/- 0.003". I shim the pos stop w/ paper when needed.

I wouldn't square anything against it as a reference.

>
> >>
>
> >> -- angle between the fence of the Incra 3000 miter gauge, and
>
> >> the miter bar (ditto)
>
>
>
> > ibid
>
>
>
> same answer

Same goes for my Osborne EB3 that hangs on a wall. It needs periodic adjusting.

>
> >>
>
> >> -- angle between the Incra 3000 and the table saw blade (ditto)
>
> >
>
> > ibid
>
>
>
> same answer

>
> >>
>
> >> -- one of my Jevons 3D squares <http://www.jevonstoolco.com/>
>
> >> -- I have no connection with the company, except as a
>
> >> *totally* satisfied customer -- these are great products, and
>
> >> as close to dead-on-perfect as a woodworking tool needs to be
>
> >> (within 0.002" in 6", according to the manufacturer)
>
> >>
>
> >> -- my crosscut sled
>
> >
>
> > ibid
>
>
>
> same answer
>
> >
>
> >>
>
> >> -- any corner of at least seven pieces of furniture in my home
>
> >> that I've made using some or all of the above
>
> >
>
> > I hope you're joking.
>
>
>
> Why would you think that?
>
>
>
> Just for giggles and grins, I just checked a corner of an end
>
> table that I made about 12 years ago -- put the head of the
>
> Starrett square against a corner of the tabletop, and tried to
>
> slip a 0.002" feeler gauge between the blade and the tabletop. It
>
> won't fit, anywhere within 7 1/2 inches of the corner.
>
>
>
> I'm satisfied with 99.97%.

On Thursday, January 3, 2013 10:19:46 PM UTC-5, Lew Hodgett wrote:
> <[email protected]> wrote:
>
>
>
> > Let me know what you guys think.
>
> -----------------------------------------------------------
>
> A slow night in the Carolinas.

Then go out and get a drink Lew! Get off yer butt! :)

>
>
>
> Lew

[email protected] writes:


>I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)
>

I don't know why google groups double-spaces every one of your posts, but it is
annoying.

Starrett is in business to supply precision tools to the metalworking and patternmaking
industries, for which a much higher level of precision is required than for building
furniture, where "within a 32nd" is usually more than sufficient.

On Thursday, January 3, 2013 9:42:29 PM UTC-5, Bill wrote:
> [email protected] wrote:
>
> > Yes they are. I am 'referring' to them in the article. It's done routinely in the literature.
>
> >> References usally means bibliographical references (to related works).
>
> > Yes, usually. It is however, not incorrect how I used the term.
>
> >
>
> >
>
> >>
>
> >>
>
> >> "Notes" may be more appropriate (I'm not looking for an argument).
>
> > I like references. It's what I'm used to.
>
> >
>
> >
>
>
>
> When you submit your work for publication, the publisher will advise you
>
> in no uncertain terms how it it should appear.

I've read more than my fair share of peer reviewed scientific publications. And as a scientist, I've written a few peer reviewed as well. I have never heard of a reviewer who had a problem with using 'References' in the fashion that I did.


>
> While your idea may be just fine, having reviewed a few books and papers
>
> before, it is my humble opinion your your paper needs work.

You can't please everyone. Isn't that what they say?

>
> I would look forward to seeing your ideas presented again. As has been
>
> suggested, this isn't rocket science, but the application of using
>
> the magnetic cubes to check for accuracy in squares is an interesting
>
> application. Why settle for good-enough.

Magnetic cubes?

>
>
>
> Bill

On Friday, January 4, 2013 11:57:39 AM UTC-5, Swingman wrote:
> On 1/4/2013 10:47 AM, -MIKE- wrote:
>
> > On 1/4/13 9:31 AM, Swingman wrote:
>
> >> On 1/4/2013 9:00 AM, Dave Balderstone wrote:
>
> >>> In article <[email protected]>, Swingman
>
> >>> <[email protected]> wrote:
>
> >>>
>
> >>>> That said, you are only as accurate as your tools allow ...
>
> >>>
>
> >>> Tools, and the material you are working. Context is a large part of it.
>
> >>
>
> >> Here, let me put back in the part you conveniently left out:
>
> >>
>
> >> "At the same time, I'm just as guilty as anyone of occasionally settling
>
> >> for less ... mainly due to time, circumstances, the medium
>
> >> (woodworking), and the need to 'git r' done'. "
>
> >>
>
> >> Notice the mention of "woodworking"?
>
> >>
>
> >> How does that not set the "context"?
>
> >>
>
> >>> A couple of thousandths over two feet is out of context for woodworking
>
> >>> joints. The material is going to move more than that simply due to
>
> >>> weather variation.
>
> >>>
>
> >>> I'd rather spend a few bucks on a quality square than putz around with
>
> >>> a dial indicator.
>
> >>
>
> >> Here, I'll say it again:
>
> >>
>
> >> You are only as accurate as your tools allow.
>
> >>
>
> >
>
> > I think most of us agree with you. I certainly do.
>
> > However, there comes a time, I would say sooner than later, when you
>
> > reach a point of diminishing returns, no?
>
>
>
> ~ A smartass, but totally accurate reply to that:
>
>
>
> End result of angular error ALWAYS increases with distance.

For some reason it is almost impossible to introduce/discuss a method that mentions the word "accuracy" without the knuckleheads screaming the tired NASA quip.

I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)



>
>
>
> ~ Cuz I love you, my friend reply:
>
>
>
> Of course there is a "point of diminishing returns" ... but that is
>
> irrelevant to my point, summed up nicely in my remarks that keep getting
>
> left out (OTHERWISE KNOW AS "CONTEXT" FOR CRISSAKES!)
>
>
>
> :)
>
>
>
> To wit:
>
>
>
> "I'm of the camp that if you don't have perfection as a goal for every
>
> step of the process, you will never scratch that itch some of us are
>
> cursed with."
>
>
>
> IOW, those looking for "context" would do well to learn to fucking READ
>
> first!
>
>
>
> :)
>
>
>
> --
>
> eWoodShop: www.eWoodShop.com
>
> Wood Shop: www.e-WoodShop.net
>
> https://plus.google.com/114902129577517371552/posts
>
> KarlCaillouet@ (the obvious)

On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in news:ee116537-b047-4754-88e2-dfc87af63570
>
> @googlegroups.com:
>
>
>
> > On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam wrote:
>
> >> Then use a marking knife.
>
> >
>
> > You're still left with not being able to quantitate the error. Are you following along?
>
> >
>
> _Of course_ you can "quantitate" [sic] the error. What makes you think it can't be measured?

Measure thousands of an inch between two lines. Sure it can be measured. Accurately? No.

On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller wrote:
> [email protected] wrote in news:bc9297af-00ce-44cd-8f63-cfff2cea2c50
>
> @googlegroups.com:
>
>
>
>
>
> > I like to have at least one master square that I know is balls to wall accurate. I had no way
>
> of checking before and I do now. The Draw-A-Line and flip method will never tell you how
>
> far out of wack your square is
>
>
>
> Pfui. Of course it will. The more the lines diverge, the more out of whack it is.

"More out of wack" is not a quantity. I can only be used in relative terms. 'This' is more out of wack than 'this'.

>
>
>
> > - only that it might be out of wack. There is no way to quantitate the angle error unless you
>
> can measure the distance betwene the lines/knife marks with a caliper (good luck).
>
>
>
> That'll work. Feeler gauges will probably work better.

Huh? Measure the distance between two lines with a feeler gauges?
>
>
>
> > How much of a gap in between the marks is considered unacceptable? You can't easily
>
> answer that question so why bother checking in the first place?
>
>
>
> Of course you can easily answer that question. Decide what percentage error is
>
> acceptable in your project, and you can easily calculate the permissible gap between the
>
> marks. Suppose you want accuracy to one part in 1000 (99.9%).

So you decide before hand the accuracy you want to achieve and then choose the appropriate square? Do you have different squares for different jobs? Are they labeled as such?

> The gap between the
>
> pencil lines at a distance of 8" -- double the error in the square, remember -- must be no
>
> more than 8 * 2/1000 = 0.016", which is easily measurable with feeler gauges, a dial caliper,
>
> or a mike.


A distance of 0.016" equates to an angle error of 0.5 degrees for your 8" square. Would you calibrate anything with that "Square"? I wouldn't.

What is your limit of detection for measuring gaps between lines? I hope it's less than 0.016", but I can understand if it's not.

On Jan 4, 6:35=A0pm, [email protected] (Larry W) wrote:
> In article <[email protected].=
com>,
> Father Haskell =A0<[email protected]> wrote:
>
>
>
>
>
>
>
>
>
> >On Jan 4, 12:26=A0pm, [email protected] (Scott Lurndal) wrote:
> >> [email protected] writes:
> >> >I'm baffled at this point that Starrett is still in business. =A0We c=
an
> >just measure our square references from our existing furniture. Right?
> >=A0:)
>
> >> I don't know why google groups double-spaces every one of your posts,
> >but it is
> >> annoying.
>
> >> Starrett is in business to supply precision tools to the metalworking
> >and patternmaking
> >> industries, for which a much higher level of precision is required
> >than for building
> >> furniture, where "within a 32nd" is usually more than sufficient.
>
> >Which is as good as a foot for a luthier, who works to
> >within 0.004" or better.
>
> Better watch out, next yhing you know Steve Strickland will be back
> explaining how to cut a board to 1/1000 of an inch on his tablesaw... =A0=
:)

Norris smoother.

On 1/4/2013 5:52 PM, Doug Winterburn wrote:
> On 01/04/2013 02:09 PM, Mike Marlow wrote:
>> Leon wrote:
>>
>>> LOL... Is this why you never post any of your work? I don't find
>>> 32's of
>>> an inch tolerances acceptable in woodworking. If you want
>>> multiple width and length pieces to fit precisely within a given
>>> constraint you have to do a lot better than 32's. A whole lot better.
>>
>> Yer killin' me here brother! How much better can you really get? How
>> much
>> better realy results in a difference in the work that you are doing I
>> understand that you may pursue a more difinitive precisions, but what
>> I am
>> asking is can you definitively define the benefit to that? So - if we
>> are
>> dealing with machinery and tools, and techinques that are less precise
>> than
>> that, can we really advocate that such degrees of precision are genuinely
>> effective? I'm not talking about what we feel is effective - I'm
>> asking you
>> to provide real measured prrof of your claim.
>>
>
> I dunno - a 1/32" difference between the end shoulders and the long
> shoulders of a tenon on a M&T joint would definitely show, especially if
> the gap created was on the long shoulder side.
>
>


Exactly but I am thinking more simply. If two pieces of wood that are
being joined together do not touch each other the joint will look bad.
And that noticeable gap is a whole lot less than 1/32"

wrote in message
news:[email protected]...

On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:
> In article <[email protected]>,
>
> <[email protected]> wrote:
>
>
>
> > Let me know what you guys think.
>
> >
>
> > I've been working on a new method (new?) for checking the squareness of
> > a
>
> > square using a dial indicator. The method works in theory. I've tried
> > it
>
> > and it seems to work in practice. A caveat is that the square needs a
> > thick
>
> > edge to support a stylus.
>
> >
>
> > I am going to work on a video demonstrating the process.
>
> >
>
> > http://www.garagewoodworks.com/square_a_square.php
>
> >
>
> > Thoughts?
>
>
>
> Seems totally unnecessary. A pencil and a straight edge (a la sheet
>
> good cutoff) is all you need to check if it's actually square. And it's
>
> fast to set up.

read the article.


A minor caveat to this method is that it can be difficult to discern
small gaps between the two pencil lines (especially with a thick pencil
lead). The most you might be able to detect is a 0.010" difference which
equates to a minimum detection of 0.036 degrees with an 8" square.
Another caveat is that the edge you place your square against must be
perfectly flat, otherwise you will not get an accurate calculation of your
square's angle error.
==============================================================================================================================================================
Use a knife to mark and do it on a flat smooth surface. MDF or. better yet,
a piece of metal covered in dykem blue. Make your line as light as possible.
Use magnifier. A discrepancy of .001 is readily visible.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The dial indicator method is 10X more accurate
===========================================================================================
Got a metal lathe? If you do, it can be used to make a master square that is
more accurate than anything you can buy for less than several hundred
dollars. Not needed though. Use the flip and mark
method.

On 1/4/2013 5:16 PM, Leon wrote:
> On 1/4/2013 3:09 PM, Mike Marlow wrote:
>> Leon wrote:
>>
>>> LOL... Is this why you never post any of your work? I don't find
>>> 32's of
>>> an inch tolerances acceptable in woodworking. If you want
>>> multiple width and length pieces to fit precisely within a given
>>> constraint you have to do a lot better than 32's. A whole lot better.
>>
>> Yer killin' me here brother! How much better can you really get? How
>> much
>> better realy results in a difference in the work that you are doing I
>> understand that you may pursue a more difinitive precisions, but what
>> I am
>> asking is can you definitively define the benefit to that? So - if we
>> are
>> dealing with machinery and tools, and techinques that are less precise
>> than
>> that, can we really advocate that such degrees of precision are genuinely
>> effective? I'm not talking about what we feel is effective - I'm
>> asking you
>> to provide real measured prrof of your claim.
>>
>
>
> Simply think, no gap in a joint. That is a tolerance much less than 1/32".
>
> Take a face frame that has two rows of drawers. 2 outer stiles, 1
> center stile. Between the stiles are rails that separate the stack of
> drawers in each row. Top and bottom rails are a total length of the
> drawer rails on each side and the center stile combined. The outer
> stiles are set apart a specific distance.
>
> If all of your stiles are not a precise width and your rails are not a
> complimentary precise width you get a gap in the joints.


Going a bit further, you learn to take measurements far more precisely
than what a 1/64" rule would yield.

A great measuring device that has infinite units of measure is

http://www.woodpeck.com/storystickpro.html

Starting at about 44 seconds in the video you are shown how to measure
"precisely" a distance and use that exact measurement to set up your
saw. I use this method on almost every job/project.

On 1/4/2013 8:06 PM, Doug Miller wrote:
> Leon <lcb11211@swbelldotnet> wrote in news:97KdnXmnLN2O8HrNnZ2dnUVZ5h-
> [email protected]:
>
>> Exactly but I am thinking more simply. If two pieces of wood that are
>> being joined together do not touch each other the joint will look bad.
>> And that noticeable gap is a whole lot less than 1/32"
>
> Quite so. Even a gap of 0.002" is readily apparent as a gap.
>


Exactly!

On 1/4/2013 9:54 PM, CW wrote:
>
>
> "Mike Marlow" wrote in message news:[email protected]...
>
> Leon wrote:
>
>> LOL... Is this why you never post any of your work? I don't find
>> 32's of an inch tolerances acceptable in woodworking. If you want
>> multiple width and length pieces to fit precisely within a given
>> constraint you have to do a lot better than 32's. A whole lot better.
>
> Yer killin' me here brother! How much better can you really get? How much
> better realy results in a difference in the work that you are doing I
> understand that you may pursue a more difinitive precisions, but what I am
> asking is can you definitively define the benefit to that? So - if we are
> dealing with machinery and tools, and techinques that are less precise than
> that, can we really advocate that such degrees of precision are genuinely
> effective? I'm not talking about what we feel is effective - I'm asking
> you
> to provide real measured prrof of your claim
> ======================================================================
> Go out and make a mortise and tennon joint with the tennon 1/32 to big.
>


Or make the tennon 1/32" too thin and see how the joint fits.

On 1/4/2013 11:22 AM, [email protected] wrote:

> For some reason it is almost impossible to introduce/discuss a method that mentions the word "accuracy" without the knuckleheads screaming the tired NASA quip.

Accuracy is a "detail" in the process.

"The devil is in the details".

"Attention to detail is the difference between mediocrity and supremacy."

Both arguably why some succeed, some don't ... in war, woodworking, or
otherwise. :)

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
KarlCaillouet@ (the obvious)

On 1/4/2013 12:37 PM, Keith Nuttle wrote:
> On 1/4/2013 1:24 PM, Swingman wrote:
>> On 1/4/2013 12:16 PM, Phil Kangas wrote:
>>> "Swingman" <[email protected]> wrote in message
>>>> On 1/4/2013 11:22 AM, [email protected]
>>>> wrote:
>>>>
>>>>> For some reason it is almost impossible to
>>>>> introduce/discuss a method that mentions the
>>>>> word "accuracy" without the knuckleheads
>>>>> screaming the tired NASA quip.
>>>>
>>>> Accuracy is a "detail" in the process.
>>>>
>>>> "The devil is in the details".
>>>>
>>>> "Attention to detail is the difference between
>>>> mediocrity and supremacy."
>>>>
>>>> Both arguably why some succeed, some don't ...
>>>> in war, woodworking, or otherwise. :)
>>>
>>> Like, measure it with a micrometer, mark it off
>>> with a tape
>>> measure and felt tip pen, then cut it off with a
>>> chain saw! ;>)}
>>
>> More like "measure twice, cut once, pound to fit". ;)
>>
> Only as a last resort should you go so low as to pound it to fit, there
> is always the chisel and the dremel.

But, but ... a REAL _manly_ woodworker only uses a hammer, saw and
screwdriver (and apparently an out of square square on occasion), so
what's with this chisel/dremel stuff??

:)

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
KarlCaillouet@ (the obvious)

On 1/4/2013 9:00 AM, Dave Balderstone wrote:
> In article <[email protected]>, Swingman
> <[email protected]> wrote:
>
>> That said, you are only as accurate as your tools allow ...
>
> Tools, and the material you are working. Context is a large part of it.

Here, let me put back in the part you conveniently left out:

"At the same time, I'm just as guilty as anyone of occasionally settling
for less ... mainly due to time, circumstances, the medium
(woodworking), and the need to 'git r' done'. "

Notice the mention of "woodworking"?

How does that not set the "context"?

> A couple of thousandths over two feet is out of context for woodworking
> joints. The material is going to move more than that simply due to
> weather variation.
>
> I'd rather spend a few bucks on a quality square than putz around with
> a dial indicator.

Here, I'll say it again:

You are only as accurate as your tools allow.

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://plus.google.com/114902129577517371552/posts
KarlCaillouet@ (the obvious)

On 1/4/2013 3:09 PM, Mike Marlow wrote:
> Leon wrote:
>
>> LOL... Is this why you never post any of your work? I don't find 32's of
>> an inch tolerances acceptable in woodworking. If you want
>> multiple width and length pieces to fit precisely within a given
>> constraint you have to do a lot better than 32's. A whole lot better.
>
> Yer killin' me here brother! How much better can you really get? How much
> better realy results in a difference in the work that you are doing I
> understand that you may pursue a more difinitive precisions, but what I am
> asking is can you definitively define the benefit to that? So - if we are
> dealing with machinery and tools, and techinques that are less precise than
> that, can we really advocate that such degrees of precision are genuinely
> effective? I'm not talking about what we feel is effective - I'm asking you
> to provide real measured prrof of your claim.
>


Simply think, no gap in a joint. That is a tolerance much less than 1/32".

Take a face frame that has two rows of drawers. 2 outer stiles, 1
center stile. Between the stiles are rails that separate the stack of
drawers in each row. Top and bottom rails are a total length of the
drawer rails on each side and the center stile combined. The outer
stiles are set apart a specific distance.

If all of your stiles are not a precise width and your rails are not a
complimentary precise width you get a gap in the joints.

On 1/4/2013 3:42 PM, Mike Marlow wrote:
> Swingman wrote:
>> On 1/4/2013 2:56 PM, Leon wrote:
>>
>>> LOL... Is this why you never post any of your work? I don't find 32's
>>> of an inch tolerances acceptable in woodworking. If you want
>>> multiple width and length pieces to fit precisely within a given
>>> constraint you have to do a lot better than 32's. A whole lot
>>> better.
>
> And you do that with what tool? A "whole lot better" better tool?
>
>
>


Yes

On 1/4/2013 3:15 PM, [email protected] wrote:
> On Friday, January 4, 2013 3:56:14 PM UTC-5, Leon wrote:
>> On 1/4/2013 11:26 AM, Scott Lurndal wrote:
>>
>>> [email protected] writes:
>>
>>>
>>
>>>
>>
>>>> I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)
>>
>>>>
>>
>>>
>>
>>> I don't know why google groups double-spaces every one of your posts, but it is
>>
>>> annoying.
>>
>>>
>>
>>> Starrett is in business to supply precision tools to the metalworking and patternmaking
>>
>>> industries, for which a much higher level of precision is required than for building
>>
>>> furniture, where "within a 32nd" is usually more than sufficient.
>>
>>>
>>
>>
>>
>>
>>
>> LOL... Is this why you never post any of your work? I don't find 32's
>>
>> of an inch tolerances acceptable in woodworking. If you want multiple
>>
>> width and length pieces to fit precisely within a given constraint you
>>
>> have to do a lot better than 32's. A whole lot better.
>
> Tight fitting half lap joints are sloppy with a 1/32" gap.
>
> http://www.youtube.com/watch?v=BExGi9HbLSM
>
> Not to mention the need for higher standards w/ regard to inlay and banding.
>

This stack of 8 muntins were made with the aid of my kerfmaker. And
each is 5/32" thick total after drum sanding. The joints are 5/64" deep.

http://www.flickr.com/photos/lcb11211/4287396695/in/set-72157622991960362/lightbox/

Correction


> If all of your stiles are not a precise width and your rails are not a
> complimentary precise LENGTH you get a gap in the joints.

On 1/4/2013 3:12 PM, Mike Marlow wrote:
> Leon wrote:
>
>>
>> For some good enough is a goal to strive for. Some of us are not
>> happy with that.
>
>
> Depends on what you call "good enough". Quit tryingt to sound like Karl.
> You know that both of you default to "good enough" in everything you do.
> You have to. There is no way in the medium in which you work, that you can
> do any differeently. So - why try to be disparaging in your post?
>


Show us some of your work Mike, I might call that good enough.

[email protected] wrote in news:bc9297af-00ce-44cd-8f63-cfff2cea2c50
@googlegroups.com:


> I like to have at least one master square that I know is balls to wall accurate. I had no way
of checking before and I do now. The Draw-A-Line and flip method will never tell you how
far out of wack your square is

Pfui. Of course it will. The more the lines diverge, the more out of whack it is.

> - only that it might be out of wack. There is no way to quantitate the angle error unless you
can measure the distance betwene the lines/knife marks with a caliper (good luck).

That'll work. Feeler gauges will probably work better.

> How much of a gap in between the marks is considered unacceptable? You can't easily
answer that question so why bother checking in the first place?

Of course you can easily answer that question. Decide what percentage error is
acceptable in your project, and you can easily calculate the permissible gap between the
marks. Suppose you want accuracy to one part in 1000 (99.9%). The gap between the
pencil lines at a distance of 8" -- double the error in the square, remember -- must be no
more than 8 * 2/1000 = 0.016", which is easily measurable with feeler gauges, a dial caliper,
or a mike.

[email protected] wrote in news:214a7bab-b962-477d-8340-
[email protected]:

> Scenario: You make it out to the woodshop after a hard night of drinking. As the
> acetaldehyde takes it's effect on you, you drop your Starrett square on the concrete floor.

Doesn't happen in my shop. That's a hard and fast safety rule here: if I drink, I stay out of the
shop until after a full night's sleep.

That doesn't mean I can't or won't ever drop the square, of course -- just means that if I do, it
will be the result of my own innate clumsiness, not of inebriation.

> What do you do? Continue to use it and hope for the best or check to see if it's still of
> 'Starrett Quality'? How do you check?

Your imagination is lacking, Brian <g>. I can think of at least half a dozen things I could
check it against:
-- angle between the jointer fence and bed (previously set using the same Starrett square)
-- angle between the fence of the Incra 3000 miter gauge, and the miter bar (ditto)
-- angle between the Incra 3000 and the table saw blade (ditto)
-- one of my Jevons 3D squares <http://www.jevonstoolco.com/> -- I have no connection
with the company, except as a *totally* satisfied customer -- these are great products, and
as close to dead-on-perfect as a woodworking tool needs to be (within 0.002" in 6",
according to the manufacturer)
-- my crosscut sled
-- any corner of at least seven pieces of furniture in my home that I've made using some or
all of the above

[email protected] wrote in news:5443d0e1-47e2-4bf4-9dc6-237d07bf6357
@googlegroups.com:

> There is no need to "try again" and I appreciate your veiled arrogance.
>
> Where are you having trouble with the math?

Ummm.... Brian, you don't know Bill personally. I do.

He's not the sort of guy to toot his own horn, so without his consent, I'm not going to say why I'm
so sure of it, but please trust me on this: the man *knows* math.

[email protected] wrote in
news:[email protected]:

> On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller
> wrote:
>> [email protected] wrote in
>> news:bc9297af-00ce-44cd-8f63-cfff2cea2c50
>>
>> @googlegroups.com:
>>
>>
>>
>>
>>
>> > I like to have at least one master square that I know is
>> > balls to wall accurate. I had no way
>>
>> of checking before and I do now. The Draw-A-Line and flip
>> method will never tell you how
>>
>> far out of wack your square is
>>
>>
>>
>> Pfui. Of course it will. The more the lines diverge, the more
>> out of whack it is.
>
> "More out of wack" is not a quantity. I can only be used in
> relative terms. 'This' is more out of wack than 'this'.

Yes, and I was using it in relative terms. Where's the problem?
>
>> > - only that it might be out of wack. There is no way to
>> > quantitate the angle error unless you
>>
>> can measure the distance betwene the lines/knife marks with a
>> caliper (good luck).
>>
>>
>>
>> That'll work. Feeler gauges will probably work better.
>
> Huh? Measure the distance between two lines with a feeler
> gauges?

Sure, why not? You can easily see if the gauge overlaps the lines
or fits between them. BTW, the width of the pencil lines isn't
really relevant -- use a marking knife instead of a pencil.
>>
>>
>>
>> > How much of a gap in between the marks is considered
>> > unacceptable? You can't easily
>>
>> answer that question so why bother checking in the first place?
>>
>>
>>
>> Of course you can easily answer that question. Decide what
>> percentage error is
>>
>> acceptable in your project, and you can easily calculate the
>> permissible gap between the
>>
>> marks. Suppose you want accuracy to one part in 1000 (99.9%).
>
> So you decide before hand the accuracy you want to achieve and
> then choose the appropriate square?

Of course.

> Do you have different squares for different jobs? Are they
> labeled as such?

I have a Starrett square that never leaves the wood shop. I also
have a Craftsman combination square, and a Stanley framing square,
that I use for carpentry projects. It never crossed my mind to use
the Starrett when I built a shed in the back yard a few years ago,
or when my son and I built a deck last summer -- that degree of
precision simply isn't needed, and there's no point in risking an
expensive precision tool on a construction site.
>
>> The gap between the pencil lines at a distance of 8" -- double
>> the error in the square, remember -- must be no more than 8 *
>> 2/1000 = 0.016", which is easily measurable with feeler gauges,
>> a dial caliper, or a mike.
>
>
> A distance of 0.016" equates to an angle error of 0.5 degrees
> for your 8" square.

No it does not.

First of all, 0.016" is double the error, so the actual error is
0.008" over 8" or 0.001. The inverse tangent of 0.001 is 0.0573
degrees (rounded to 3 significant digits). If you want to be
really picky, the 8" distance is actually the hypotenuse of the
triangle, so we should use inverse sine instead, but the result is
the same to at least the seventh decimal place.

>Would you calibrate anything with that "Square"? I wouldn't.

I wouldn't either -- *if* your number was right. It's not, though,
and I'm not sure why you seem to have a problem with using a
square that's accurate to one part in a thousand for woodworking.

> What is your limit of detection for measuring gaps between
> lines? I hope it's less than 0.016", but I can understand if
> it's not.

I can estimate much finer gaps than that by eye. The thinnest
feeler gauge I own is 0.001"; anything less than that is too
fragile for wood shop use, and is pointless anyway. In practice, a
0.002" gauge is quite sufficient for woodworking.

[email protected] wrote in
news:[email protected]:

> On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller
> wrote:
>> [email protected] wrote in
>> news:214a7bab-b962-477d-8340-
>>
>> [email protected]:
>>
>>
>>
>> > Scenario: You make it out to the woodshop after a hard night
>> > of drinking. As the acetaldehyde takes it's effect on you,
>> > you drop your Starrett square on the concrete floor.
>>
>>
>>
>> Doesn't happen in my shop. That's a hard and fast safety rule
>> here: if I drink, I stay out of the shop until after a full
>> night's sleep.
>>
>> That doesn't mean I can't or won't ever drop the square, of
>> course -- just means that if I do, it will be the result of my
>> own innate clumsiness, not of inebriation.
>>
>> > What do you do? Continue to use it and hope for the best or
>> > check to see if it's still of
>> > 'Starrett Quality'? How do you check?
>>
>> Your imagination is lacking, Brian <g>. I can think of at least
>> half a dozen things I could check it against:
>>
>> -- angle between the jointer fence and bed (previously set
>> using the same Starrett square)
>
> How can you be sure it's still square to the level of accuracy
> required?

I check it periodically, using both the Starrett and the Jevons
squares. Don't you?
>>
>> -- angle between the fence of the Incra 3000 miter gauge, and
>> the miter bar (ditto)

> ibid

same answer
>>
>> -- angle between the Incra 3000 and the table saw blade (ditto)
>
> ibid

same answer
>>
>> -- one of my Jevons 3D squares <http://www.jevonstoolco.com/>
>> -- I have no connection with the company, except as a
>> *totally* satisfied customer -- these are great products, and
>> as close to dead-on-perfect as a woodworking tool needs to be
>> (within 0.002" in 6", according to the manufacturer)
>>
>> -- my crosscut sled
>
> ibid

same answer
>
>>
>> -- any corner of at least seven pieces of furniture in my home
>> that I've made using some or all of the above
>
> I hope you're joking.

Why would you think that?

Just for giggles and grins, I just checked a corner of an end
table that I made about 12 years ago -- put the head of the
Starrett square against a corner of the tabletop, and tried to
slip a 0.002" feeler gauge between the blade and the tabletop. It
won't fit, anywhere within 7 1/2 inches of the corner.

I'm satisfied with 99.97%.

[email protected] wrote in news:ee116537-b047-4754-88e2-dfc87af63570
@googlegroups.com:

> On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam wrote:
>> Then use a marking knife.
>
> You're still left with not being able to quantitate the error. Are you following along?
>
_Of course_ you can "quantitate" [sic] the error. What makes you think it can't be measured?

[email protected] wrote in news:bccdd6ea-eb29-401f-8b92-b76c1cb38818
@googlegroups.com:

> That's not how the math is done.

LMAO
>
> If your gap between the two lines (drawn from the same point) is 0.016" then half the
distance is 0.008" which is your "Opposite Side". Now I understand the confusion here.
>
> See:
> http://www.garagewoodworks.com/angle_math.php?adjacent=8&opposite=0.008&angle=
>
> Your Opposite side is 0.008". The Adjacent side is 8".

And tangent = opposite / adjacent = 0.008 / 8 = 0.001.

(As I noted previously, the 8" is actually the hypotenuse, not the adjacent side, but for
angles this small, it doesn't matter.)

Anyway... arctan (0.001) IS NOT 0.5 degrees. You're off by an order of magnitude.
[...]
>> > What is your limit of detection for measuring gaps between
>> > lines? I hope it's less than 0.016", but I can understand if
>> > it's not.
>>
>> I can estimate much finer gaps than that by eye.
>
> And I once caught a fish ------This Big------.

If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without
using precision equipment, then you need to visit an optometrist. Seriously.

[email protected] wrote in
news:[email protected]:

> On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller
> wrote:
>> [email protected] wrote in
>> news:ee116537-b047-4754-88e2-dfc87af63570
>>
>> @googlegroups.com:
>>
>>
>>
>> > On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam
>> > wrote:
>>
>> >> Then use a marking knife.
>>
>> >
>>
>> > You're still left with not being able to quantitate the
>> > error. Are you following along?
>>
>> >
>>
>> _Of course_ you can "quantitate" [sic] the error. What makes
>> you think it can't be measured?
>
> Measure thousands of an inch between two lines. Sure it can be
> measured. Accurately? No.
>
What makes you think that? Do you own a set of feeler gauges?

[email protected] wrote in news:c844cf2e-258c-4d91-bdd5-
[email protected]:

>
> Crap, you're right. It is 0.057. I misread a decimal place. Apologies.
>
Accepted. Thank you.

[email protected] wrote in news:6bb06987-59c5-4cc0-a902-
[email protected]:

> I periodically check my jointer fence with a dial indicator (Powermatic) and it's always off by
+/- 0.003". I shim the pos stop w/ paper when needed.
>
> I wouldn't square anything against it as a reference.

It is at least close enough to tell you if you've damaged a precision square by dropping it on
the floor...

Ed Pawlowski <[email protected]> wrote in news:62kce89sa9i1ad6g19q28uajp7vharjmau@
4ax.com:

> On Thu, 03 Jan 2013 19:09:31 -0600, -MIKE- <[email protected]>
> wrote:
>>
>>Again, we're back to my original point. We're talking woodworking. How
>>exact does a 2' square need to be?
>
> If I can't see it in the finished product, it is close enough. If a
> bookcase does not rack and fall down, it is square enough.

<g>

Some years ago, I formulated these rules of thumb. If a piece of any significant size is out of
square, level, or plumb by...

1 part in 100 -- *immediately obvious* to a casual observer (don't believe me? get a level
and check, the next time it's immediately obvious that a picture on your wall doesn't hang
straight)

1 part in 200 -- apparent to anyone who is looking for flaws

1 part in 400 -- won't be seen, but can be readily found with common carpentry tools (level,
tape measure, etc)

1 part in 800 -- can't be found without precision measuring tools

The significance of these rules is that the accuracy of your work won't be any better than the
accuracy of the tools you produce it with (e.g. you can't get 1 part in 800 results with a
"square" that measures 89.7 degrees).

[email protected] wrote in news:cfc901eb-e547-4589-a3e9-
[email protected]:

> I have never needed feeler gauges. They work on a very basic principle and I feel confident
making that claim.
>

I hope you'll pardon this small correction: you have never *perceived* the need for feeler
gauges.

IMHO you should reevaluate that perception.

[email protected] wrote in news:2c3d3ffb-c20b-43fd-bcae-d1b6b820fe51
@googlegroups.com:

>> If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without
>
>
> I can discern a difference. But i wouldn't be able to quantitate the two gaps to the level of
accuracy required. And neither can you.

Don't tell me what I can and can't do.

You don't own feeler gauges, so you don't know how small a gap is visible, or how accurately
it can be estimated with a little practice.

Swingman <[email protected]> wrote in news:2JydnR1X-
[email protected]:

> On 1/4/2013 12:06 PM, -MIKE- wrote:
>> So if you're square is off by 1/10 the width of an atom, you're not very
>> good. :-P
>
> LOL ... it depends upon which atom. You never know when working with
> planks when the Planck constant might come in handy. :)
>
ba-da-BING!

[email protected] (Larry W) wrote in news:kc7ovb$2t8$1
@speranza.aioe.org:

> Better watch out, next yhing you know Steve Strickland will be back
> explaining how to cut a board to 1/1000 of an inch on his tablesaw... :)
>
Oh, my. I'm surprised anyone remembers that. IIRC, though, Steve was claiming +/- 0.0001, not
0.001, wasn't he?

Leon <lcb11211@swbelldotnet> wrote in news:97KdnXmnLN2O8HrNnZ2dnUVZ5h-
[email protected]:

> Exactly but I am thinking more simply. If two pieces of wood that are
> being joined together do not touch each other the joint will look bad.
> And that noticeable gap is a whole lot less than 1/32"

Quite so. Even a gap of 0.002" is readily apparent as a gap.

"CW" <[email protected]> wrote in
news:[email protected]:

>
>
> "Mike Marlow" wrote in message news:[email protected]...
>
> Yer killin' me here brother! How much better can you really get? How much
> better realy results in a difference in the work that you are doing I
> understand that you may pursue a more difinitive precisions, but what I am
> asking is can you definitively define the benefit to that? So - if we are
> dealing with machinery and tools, and techinques that are less precise than
> that, can we really advocate that such degrees of precision are genuinely
> effective? I'm not talking about what we feel is effective - I'm asking you
> to provide real measured prrof of your claim
> ======================================================================
> Go out and make a mortise and tennon joint with the tennon 1/32 to big.

That's an easier problem to fix than making them 1/32" too small... ;-)

Doug Winterburn <[email protected]> wrote in news:50e8369f$0$26863$c3e8da3
[email protected]:

> On 01/05/2013 07:10 AM, Doug Miller wrote:
>> "CW" <[email protected]> wrote in
>> news:[email protected]:
>>
>>>
>>>
>>> "Mike Marlow" wrote in message news:[email protected]...
>>>
>>> Yer killin' me here brother! How much better can you really get? How much
>>> better realy results in a difference in the work that you are doing I
>>> understand that you may pursue a more difinitive precisions, but what I am
>>> asking is can you definitively define the benefit to that? So - if we are
>>> dealing with machinery and tools, and techinques that are less precise than
>>> that, can we really advocate that such degrees of precision are genuinely
>>> effective? I'm not talking about what we feel is effective - I'm asking you
>>> to provide real measured prrof of your claim
>>> ======================================================================
>>> Go out and make a mortise and tennon joint with the tennon 1/32 to big.
>>
>> That's an easier problem to fix than making them 1/32" too small... ;-)
>>
> BTDT - glue on some thin stock to the tenon cheeks and re-cut.
>
Yep. Got the tee-shirt, too.

wrote in message
news:[email protected]...

On Thursday, January 3, 2013 6:57:37 PM UTC-5, -MIKE- wrote:
> On 1/3/13 5:30 PM, [email protected] wrote:
>
> > A minor caveat to this method is that it can be difficult to discern
>
> > small gaps between the two pencil lines (especially with a thick
>
> > pencil lead).
>
>
>
> Use a knife.
>
>
>
>
>
> > The most you might be able to detect is a 0.010"
>
> > difference which equates to a minimum detection of 0.036 degrees with
>
> > an 8" square. Another caveat is that the edge you place your square
>
> > against must be perfectly flat, otherwise you will not get an
>
> > accurate calculation of your square's angle error.
>
> >
>
> >
>
> > The dial indicator method is 10X more accurate.
>
> >
>
>
>
> Great, if we need to send a rocket into space, but not necessary for
>
> woodworking. :-)

I like to have at least one master square that I know is balls to wall
accurate. I had no way of checking before and I do now. The Draw-A-Line
and flip method will never tell you how far out of wack your square is -
only that it might be out of wack. There is no way to quantitate the angle
error unless you can measure the distance betwene the lines/knife marks with
a caliper (good luck). How much of a gap in between the marks is considered
unacceptable? You can't easily answer that question so why bother checking
in the first place?
====================================================================================================================================================
There are a number of ways to measure that gap. With the tools that I know
you have, a drill press, a dial indicator, a piece of chewing gum (pre
chewed) and a pin will allow you to measure to .002 or less.


>
>
>
> --
>
>
>
> -MIKE-
>
>
>
> "Playing is not something I do at night, it's my function in life"
>
> --Elvin Jones (1927-2004)
>
> --
>
> http://mikedrums.com
>
> [email protected]
>
> ---remove "DOT" ^^^^ to reply

On 1/4/2013 10:30 PM, Mike Marlow wrote:
> Leon wrote:
>> On 1/4/2013 3:12 PM, Mike Marlow wrote:
>>> Leon wrote:
>>>
>>>>
>>>> For some good enough is a goal to strive for. Some of us are not
>>>> happy with that.
>>>
>>>
>>> Depends on what you call "good enough". Quit tryingt to sound like
>>> Karl. You know that both of you default to "good enough" in
>>> everything you do. You have to. There is no way in the medium in
>>> which you work, that you can do any differeently. So - why try to
>>> be disparaging in your post?
>>
>>
>> Show us some of your work Mike, I might call that good enough.
>
> Oh no you don't! I have seen your work and I would not expect you to
> consider my work good enough. I'd be disappointed if you did. It's usually
> as good as I can get it but that's a whole different thing. Every project
> improves on the last, but there's still a good ways to go.
>

So Mike keep working at it. I have been at this seriously for the past
30 years. I would say that in the past 4~5 years I have put out the
most and best work I have ever done.

Why so much better and why more out put in shorter periods of time? The
right tools.

One of my most valuable tools is Sketchup! With this program I am
designing way more intricate and complicated pieces of furniture than I
ever dreamed of making in the past. The trick is to be able to actually
assemble the design. With Sketchup you can determine at no cost whether
the design is going to work. After that disassemble the components of
the drawing and duplicate them exactly in the shop.

Literally you build it on the computer then you build it the same in the
shop.

Add to that tools that work the way you expect them to work.,

On 1/4/2013 6:20 PM, Swingman wrote:
> On 1/4/2013 5:52 PM, Doug Winterburn wrote:
>> On 01/04/2013 02:09 PM, Mike Marlow wrote:
>>> Leon wrote:
>>>
>>>> LOL... Is this why you never post any of your work? I don't find
>>>> 32's of
>>>> an inch tolerances acceptable in woodworking.
>
>>> that, can we really advocate that such degrees of precision are
>>> genuinely
>>> effective? I'm not talking about what we feel is effective - I'm
>>> asking you
>>> to provide real measured prrof of your claim.
>>>
>>
>> I dunno - a 1/32" difference between the end shoulders and the long
>> shoulders of a tenon on a M&T joint would definitely show, especially if
>> the gap created was on the long shoulder side.
>
> Absolutely correct!
>
> BTW, here's that "measured proof", as requested above, that someone
> should NOT "...find 32's of an inch tolerances acceptable in woodworking.":
>
> https://picasaweb.google.com/111355467778981859077/EWoodShopJustStuff#5829750834071569842
>
>
> :)
>


And something tells me that you have only inserted part of the the wedge
portion of that 1/32" shim.

On Thursday, January 3, 2013 7:46:14 PM UTC-5, -MIKE- wrote:
> On 1/3/13 6:40 PM, [email protected] wrote:
>
> >>
>
> >>
>
> >> Yeah, ok man... good luck with those rocket ships. :-)
>
> >
>
> > Instead of being a fucking smart ass why don't you try answering my questions? :)
>
> >
>
> >
>
>
>
> Touchy, touchy. Why do you need to know how far out it is?

How do you know when to throw away the square? Where do you draw the line (pun intended)?

>Do you have
>
> an adjustment method that you dial in an amount and it corrects that much?

No. But I'll know what contributed to my joints not being square.

>
>
>
> As far as I know, the adjustment method is literally hit and miss. You
>
> punch the outside of the corner with a nail set to bring in an obtuse
>
> angle and punch the inside to push out an acute angle.
>
>
>
> You repeat the test and if it's pushed or pulled too far, oops, try again.



>
>
>
>
>
> --
>
>
>
> -MIKE-
>
>
>
> "Playing is not something I do at night, it's my function in life"
>
> --Elvin Jones (1927-2004)
>
> --
>
> http://mikedrums.com
>
> [email protected]
>
> ---remove "DOT" ^^^^ to reply

On 1/4/2013 11:26 AM, Scott Lurndal wrote:
> [email protected] writes:
>
>
>> I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)
>>
>
> I don't know why google groups double-spaces every one of your posts, but it is
> annoying.
>
> Starrett is in business to supply precision tools to the metalworking and patternmaking
> industries, for which a much higher level of precision is required than for building
> furniture, where "within a 32nd" is usually more than sufficient.
>


LOL... Is this why you never post any of your work? I don't find 32's
of an inch tolerances acceptable in woodworking. If you want multiple
width and length pieces to fit precisely within a given constraint you
have to do a lot better than 32's. A whole lot better.

On Friday, January 4, 2013 12:26:27 PM UTC-5, Scott Lurndal wrote:
> [email protected] writes:
>
>
>
>
>
> >I'm baffled at this point that Starrett is still in business. We can just measure our square references from our existing furniture. Right? :)
>
> >
>
>
>
> I don't know why google groups double-spaces every one of your posts, but it is
>
> annoying.

I left out:

Stop reading my posts.


>
>
> Starrett is in business to supply precision tools to the metalworking and patternmaking
>
> industries, for which a much higher level of precision is required than for building
>
> furniture, where "within a 32nd" is usually more than sufficient.

On Thursday, January 3, 2013 7:24:24 PM UTC-5, Bill wrote:
> [email protected] wrote:
>
> > Let me know what you guys think.
>
> >
>
> > I've been working on a new method (new?) for checking the squareness of a square using a dial indicator. The method works in theory. I've tried it and it seems to work in practice. A caveat is that the square needs a thick edge to support a stylus.
>
> >
>
> > I am going to work on a video demonstrating the process.
>
> >
>
> > http://www.garagewoodworks.com/square_a_square.php
>
> >
>
> > Thoughts?
>
>
>
> Sinced/dx (arctan) is close to 1 near 0, yourerror is not very big, but
>
> your equation which divides an angle by L (before applying arctan)
>
> doesn't make sense. For instance, it suggests that if you choose L
>
> great enough that your error will be as small as you need it to be.

For the same angle error, as L get longer so does abs(Delta1 - Delta2).

> I
>
> did not try to redo your derivations, but I am willing to do so if we
>
> don't find a concensus. By the way,you might sketch a triangle
>
> somewhere(tan = opp/adj)for those that may be a bit rusty at doing trig.
>
>
>
> Bill