I made a new joint

On May 17, 8:27=A0pm, David Nebenzahl <[email protected]> wrote:
> Actually discovered a variation of a joint I discovered some time ago.
>
> Way back in the 19-ought-80s, I invented a 3-member lap joint trying to
> join three stretchers on a small table (I made the joint but never
> finished the table). It was published by /Fine Woodworking/ in their
> "Methods of Work" column, and later included in a couple of their
> collections of /Proven Shop Tips/:http://www.geocities.com/bonezphoto/woo=
d/3-memberLapJoint.gif
>
> Just a few days ago I sat down to design some parts to the wooden tripod
> I'm building, and remembered this joint. However, after making some
> sketches and a cardboard mock-up, I realized that this joint could be
> made much more simply:http://www.geocities.com/bonezphoto/wood/3-memberLa=
pJointNew.gif
>
> While the original joint is stronger since it has a larger glue surface
> area, the new variant is much easier to make. In fact, I did the whole
> thing on the table saw, where in the original joint you have to chop out
> half of the waste. And I'm not the best wood-chopper-outer in the world,
> I'll admit. Hard to keep those surfaces flat enough for gluing.
>
> The new joint is an interesting little puzzle that I haven't completely
> figured out yet. Because of its asymmetry, it needs to be made oversize
> to cover the needed width. The finished joint looks nice, though not as
> interesting as the original with its angular inlets.

I like the original design, too. It's got a Chinese/Japanese flavor
to it. Seems to me you could use a jig and router and knock out
either joint fairly easily with just a little bit of handwork.

Are you still in Flagstaff? I rode through there on my bicycle on my
way cross country back when your Methods of Work tip appeared. Great
area.

R

On May 18, 9:03=A0pm, David Nebenzahl <[email protected]> wrote:
> On 5/18/2009 12:58 PM Lowell Holmes spake thus:
>
>
>
>
>
> > "RicodJour" <[email protected]> wrote in message
> >news:71feef8c-32ca-4619-9e2b-3892fe115cfa@n21g2000vba.googlegroups.com..=
.
>
> > On May 18, 10:09 am, Morris Dovey <[email protected]> wrote:
>
> >> Lowell Holmes wrote:
>
> >>> I was successful in posting a pdf of the joint. The joint needs to be
> >>> modified in order to fill the voids. That would be easy to do. I'm no=
t
> >>> sure
> >>> it could be done on a table saw.
>
> >> Me too - but when I tried to do the modification (by shifting the
> >> "center" toward the side), I still couldn't make it work. I'm not
> >> certain that I couldn't have done better with another cup of coffee,
> >> but...
>
> > Obvious solution - get a bigger cup. =A0;)
>
> > I went to the shop and made a rough try at David's original joint. I ha=
d to
> > make a slight change from what my understanding is, but it did make up.=
The
> > work I did is rough and not close tolerance, but you can see the joint
> > works. I posted photos in abpw news group.
>
> Now that you've made it, you should try to make some variations with n
> members (4,5,6, etc.). It'll work with any number of pieces (well,
> within reason).
>
> I'm just afraid that the 4-member one will have a center that looks like
> a swastika ...

The swastika is an ancient good luck symbol that was co-opted by the
Nazis. I was surprised to see a baby carriage with a swastika on it
in an antique store. It was a Victorian carriage. In India you will
still see swastikas on shrines and houses.

A perfectly good symbol stolen by perfectly evil people.

R

<[email protected]> wrote in message
news:99062981-4e9a-43bc-a016-61841b01efe7@u10g2000vbd.googlegroups.com...
> "Way back in the 19-ought-80s"
>
> Wouldn't that translate to 19080?
>
> 1908 is aught-eight, no?


I thought 2008 was aught-eight.

On May 19, 4:17=A0am, David Nebenzahl <[email protected]> wrote:
>
> Thanks. Since you like the design, you might find this variation
> interesting:http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.=
gif
>
> Came up with it while doodling designs for the tripod, but after making
> a mock-up decided it was too much work for this project. I like the
> circular motif.

How would you assemble that joint? It seems that you'd need fairly
loose fitting joinery and fairly thin pieces.

R

On May 19, 2:07=A0pm, David Nebenzahl <[email protected]> wrote:
> On 5/19/2009 5:46 AM RicodJour spake thus:
>
> > On May 19, 4:17 am, David Nebenzahl <[email protected]> wrote:
>
> >> Thanks. Since you like the design, you might find this variation
> >> interesting:http://www.geocities.com/bonezphoto/wood/3-memberLapJointC=
ir.gif
>
> >> Came up with it while doodling designs for the tripod, but after makin=
g
> >> a mock-up decided it was too much work for this project. I like the
> >> circular motif.
>
> > How would you assemble that joint? =A0It seems that you'd need fairly
> > loose fitting joinery and fairly thin pieces.
>
> What do you mean? It should fit tight as a drum.
>
> It is a bit of a puzzle, so maybe you just need to visualize how it
> comes together. (Took me a while, and I'm the one who dreamt it up.)

I did visualize it, and I visualized a problem. You have tight
joints, all square corners and edges, the first two pieces slide
together, what happens with the third? It has to be twisted into
place, and if you have exact cuts and square edges, where's the leeway
to assemble it? You could undercut the joints so only the top edge is
tight, but that presents other problems.

> There is some waste, sure, since the legs are narrower than the center
> of the joint, but that happens many places in woodworking. We love to
> waste wood!

The waste is not an issue in my mind if the joint goes together. If
the joint doesn't go together and fit tightly, well, then you get 100%
waste!

R

"RicodJour" <[email protected]> wrote in message
news:71feef8c-32ca-4619-9e2b-3892fe115cfa@n21g2000vba.googlegroups.com...
On May 18, 10:09 am, Morris Dovey <[email protected]> wrote:
> Lowell Holmes wrote:
> > I was successful in posting a pdf of the joint. The joint needs to be
> > modified in order to fill the voids. That would be easy to do. I'm not
> > sure
> > it could be done on a table saw.
>
> Me too - but when I tried to do the modification (by shifting the
> "center" toward the side), I still couldn't make it work. I'm not
> certain that I couldn't have done better with another cup of coffee,
> but...

Obvious solution - get a bigger cup. ;)

R
I tried that also. I think the original joint with some hand work is the way
to go. It would not take much time at all to do. I may go to the shop and
try one just to see. If I do, I will post a picture.

David Nebenzahl wrote:
> Actually discovered a variation of a joint I discovered some time ago.
>
> Way back in the 19-ought-80s, I invented a 3-member lap joint trying to
> join three stretchers on a small table (I made the joint but never
> finished the table). It was published by /Fine Woodworking/ in their
> "Methods of Work" column, and later included in a couple of their
> collections of /Proven Shop Tips/:
> http://www.geocities.com/bonezphoto/wood/3-memberLapJoint.gif

I like it!

> Just a few days ago I sat down to design some parts to the wooden tripod
> I'm building, and remembered this joint. However, after making some
> sketches and a cardboard mock-up, I realized that this joint could be
> made much more simply:
> http://www.geocities.com/bonezphoto/wood/3-memberLapJointNew.gif

Neat, but not as pleasing (to me) as the original.

> While the original joint is stronger since it has a larger glue surface
> area, the new variant is much easier to make. In fact, I did the whole
> thing on the table saw, where in the original joint you have to chop out
> half of the waste. And I'm not the best wood-chopper-outer in the world,
> I'll admit. Hard to keep those surfaces flat enough for gluing.

Sometime over the summer (or perhaps next winter) I think I'll have to
try writing a short CNC router program for a close variant of the
original. It's just too interesting to not try! :)

Thank you for sharing both joints.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

Tom Veatch wrote:

> I agree it's a puzzle. I've failed so far to lay out an arrangement
> that can be cut with a table saw where the side not shown in your
> sketched plan view isn't full of gaps, voids, and/or mismatched edges.

Good catch - I fired up DesignCAD and confess that I couldn't make the
geometry (as drawn) work either. Perhaps Dave is remembering another
joint...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

Lowell Holmes wrote:

> I was successful in posting a pdf of the joint. The joint needs to be
> modified in order to fill the voids. That would be easy to do. I'm not sure
> it could be done on a table saw.

Me too - but when I tried to do the modification (by shifting the
"center" toward the side), I still couldn't make it work. I'm not
certain that I couldn't have done better with another cup of coffee, but...

> The sketch shows a single part and then three parts assembled. And then I
> showed a rotated view of the same assembly.
>
> I think it is an ingenious solution.

I think the original joint was the truly ingenious one. So ingenious
that I've stashed it in my "must try" collection (even though I don't
build furniture).

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

On 5/18/2009 2:06 AM Morris Dovey spake thus:

> Tom Veatch wrote:
>
>> I agree it's a puzzle. I've failed so far to lay out an arrangement
>> that can be cut with a table saw where the side not shown in your
>> sketched plan view isn't full of gaps, voids, and/or mismatched edges.
>
> Good catch - I fired up DesignCAD and confess that I couldn't make the
> geometry (as drawn) work either. Perhaps Dave is remembering another
> joint...

My bad; I probably should have been clearer.

The joint is shown correctly, and the finished joint as well. But what I
left out is that the joint will have voids on the sides. (This is what I
meant by the "puzzle" part of this joint; I still haven't figured out
how to lay it out to minimize the waste, or to maximize the width.)

The original joint doesn't have this flaw, but then it's a lot harder to
make. (Unless, of course, you set up your CNC machine to cut it. But
even then you'll have to finish the sharp corners by hand.)


--
Found--the gene that causes belief in genetic determinism

On 5/18/2009 12:58 PM Lowell Holmes spake thus:

> "RicodJour" <[email protected]> wrote in message
> news:71feef8c-32ca-4619-9e2b-3892fe115cfa@n21g2000vba.googlegroups.com...
>
> On May 18, 10:09 am, Morris Dovey <[email protected]> wrote:
>
>> Lowell Holmes wrote:
>>
>>> I was successful in posting a pdf of the joint. The joint needs to be
>>> modified in order to fill the voids. That would be easy to do. I'm not
>>> sure
>>> it could be done on a table saw.
>>
>> Me too - but when I tried to do the modification (by shifting the
>> "center" toward the side), I still couldn't make it work. I'm not
>> certain that I couldn't have done better with another cup of coffee,
>> but...
>
> Obvious solution - get a bigger cup. ;)
>
> I went to the shop and made a rough try at David's original joint. I had to
> make a slight change from what my understanding is, but it did make up. The
> work I did is rough and not close tolerance, but you can see the joint
> works. I posted photos in abpw news group.

Now that you've made it, you should try to make some variations with n
members (4,5,6, etc.). It'll work with any number of pieces (well,
within reason).

I'm just afraid that the 4-member one will have a center that looks like
a swastika ...


--
Found--the gene that causes belief in genetic determinism

On 5/18/2009 6:21 PM RicodJour spake thus:

> On May 18, 9:03 pm, David Nebenzahl <[email protected]> wrote:
>
>> I'm just afraid that the 4-member one will have a center that looks like
>> a swastika ...
>
> The swastika is an ancient good luck symbol that was co-opted by the
> Nazis. I was surprised to see a baby carriage with a swastika on it
> in an antique store. It was a Victorian carriage. In India you will
> still see swastikas on shrines and houses.
>
> A perfectly good symbol stolen by perfectly evil people.

Oh, yeah, I know that--used by American Indians, etc.

I really have nothing against the swastika, even though I'm a Jew. Hell,
I even have something in my house that has a swastika (*the* swastika)
on it: a phony-baloney "Leica" (actually a Soviet FED) inscribed on top
with "1936 Olympia Berlin" with the eagle-clutching-swastika emblem
below the Olympic rings. As phony as a 3 dollar bill (but actually not a
bad camera).

Don't think I'll be using it as a motif on any of my projects, though.


--
Found--the gene that causes belief in genetic determinism

David Nebenzahl wrote:

> My bad; I probably should have been clearer.

Clarity is good - or so I was telling myself at 4am :)

> The joint is shown correctly, and the finished joint as well. But what I
> left out is that the joint will have voids on the sides. (This is what I
> meant by the "puzzle" part of this joint; I still haven't figured out
> how to lay it out to minimize the waste, or to maximize the width.)
>
> The original joint doesn't have this flaw, but then it's a lot harder to
> make. (Unless, of course, you set up your CNC machine to cut it. But
> even then you'll have to finish the sharp corners by hand.)

Actually, you did a such a great job with the original that I'm not very
concerned with the second (but put me on your mailing list for when you
make the second work without voids!).

I /will/ eventually CNC cut the original - and won't need to finish the
sharp corners by hand. The top three photos at

http://www.iedu.com/DeSoto/Projects/Bevel/

illustrate CNC routing done with a 1/32" (0.79375 mm) bit, which would
leave a 1/64" radius at (only) the three inner points. If you didn't
already know what to look for, they'd look sharp. I've seen 1/64" bits
advertised, but why bother? :)

By the way, the photo at the bottom of that page shows a 1/4" tenon cut
on the end of a 1/4" thick board - with a shoulder all the way around. :)

And to return the favor you've done me, I have a lap/scarf joint you
might find interesting. It demonstrates a bit of what becomes possible
with CNC cutting.

http://www.iedu.com/DeSoto/Projects/LLJ/

Finally (to get even with you for not telling me about those voids!), at

http://www.iedu.com/DeSoto/Projects/JBot/

there're photos of a DIY CNC router with a 1/4800" step size intended
just for joinery operations - and I think you might have a lot of fun
with something like. Best off all, it took less than a half-sheet of
3/4" Baltic birch...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/

On 5/18/2009 7:09 AM Morris Dovey spake thus:

> I think the original joint was the truly ingenious one. So ingenious
> that I've stashed it in my "must try" collection (even though I don't
> build furniture).

Thanks. Since you like the design, you might find this variation
interesting:
http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.gif

Came up with it while doodling designs for the tripod, but after making
a mock-up decided it was too much work for this project. I like the
circular motif.

Put that in your CNC program and smoke it!


--
Found--the gene that causes belief in genetic determinism

On 5/19/2009 5:46 AM RicodJour spake thus:

> On May 19, 4:17 am, David Nebenzahl <[email protected]> wrote:
>>
>> Thanks. Since you like the design, you might find this variation
>> interesting:http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.gif
>>
>> Came up with it while doodling designs for the tripod, but after making
>> a mock-up decided it was too much work for this project. I like the
>> circular motif.
>
> How would you assemble that joint? It seems that you'd need fairly
> loose fitting joinery and fairly thin pieces.

What do you mean? It should fit tight as a drum.

It is a bit of a puzzle, so maybe you just need to visualize how it
comes together. (Took me a while, and I'm the one who dreamt it up.)

There is some waste, sure, since the legs are narrower than the center
of the joint, but that happens many places in woodworking. We love to
waste wood!


--
Found--the gene that causes belief in genetic determinism

On 5/19/2009 11:07 AM David Nebenzahl spake thus:

> On 5/19/2009 5:46 AM RicodJour spake thus:
>
>> On May 19, 4:17 am, David Nebenzahl <[email protected]> wrote:
>>>
>>> Thanks. Since you like the design, you might find this variation
>>> interesting:http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.gif
>>>
>>> Came up with it while doodling designs for the tripod, but after making
>>> a mock-up decided it was too much work for this project. I like the
>>> circular motif.
>>
>> How would you assemble that joint? It seems that you'd need fairly
>> loose fitting joinery and fairly thin pieces.
>
> What do you mean? It should fit tight as a drum.

Dang. Now I'm gonna have to actually make this sucker to see if it can
be assembled without resorting to hammers and such.


--
Found--the gene that causes belief in genetic determinism

On 5/20/2009 6:27 PM [email protected] spake thus:

> "Way back in the 19-ought-80s"
>
> Wouldn't that translate to 19080?

Not to anyone with an intact sense of humor.

> 1908 is aught-eight, no?


--
Found--the gene that causes belief in genetic determinism

On May 18, 10:09=A0am, Morris Dovey <[email protected]> wrote:
> Lowell Holmes wrote:
> > I was successful in posting a pdf of the joint. The joint needs to be
> > modified in order to fill the voids. That would be easy to do. I'm not =
sure
> > it could be done on a table saw.
>
> Me too - but when I tried to do the modification (by shifting the
> "center" toward the side), I still couldn't make it work. I'm not
> certain that I couldn't have done better with another cup of coffee, but.=
..

Obvious solution - get a bigger cup. ;)

R

"Morris Dovey" <[email protected]> wrote in message
news:[email protected]...
> Lowell Holmes wrote:
>
>> I was successful in posting a pdf of the joint. The joint needs to be
>> modified in order to fill the voids. That would be easy to do. I'm not
>> sure it could be done on a table saw.
>
> Me too - but when I tried to do the modification (by shifting the "center"
> toward the side), I still couldn't make it work. I'm not certain that I
> couldn't have done better with another cup of coffee, but...
>
>> The sketch shows a single part and then three parts assembled. And then
>> I showed a rotated view of the same assembly.
>>
>> I think it is an ingenious solution.
>
> I think the original joint was the truly ingenious one. So ingenious that
> I've stashed it in my "must try" collection (even though I don't build
> furniture).
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USA
> http://www.iedu.com/DeSoto/

I don't disagree with you at all.

I tend to try keeping things simple. I might very well use the second method
and glue blocks in the void. You could also taper the boards to fill the
void. You might even make it a design element.

On May 19, 8:46=A0am, RicodJour <[email protected]> wrote:
> On May 19, 4:17=A0am, David Nebenzahl <[email protected]> wrote:
>
>
>
> > Thanks. Since you like the design, you might find this variation
> > interesting:http://www.geocities.com/bonezphoto/wood/3-memberLapJointCi=
r.gif
>
> > Came up with it while doodling designs for the tripod, but after making
> > a mock-up decided it was too much work for this project. I like the
> > circular motif.
>
> How would you assemble that joint? =A0It seems that you'd need fairly
> loose fitting joinery and fairly thin pieces.
>
> R

Not to mention the amount of wasted material to make it (out of one
piece)

"Way back in the 19-ought-80s"

Wouldn't that translate to 19080?

1908 is aught-eight, no?

"Lowell Holmes" <[email protected]> wrote in message
news:[email protected]...
>
> "Morris Dovey" <[email protected]> wrote in message
> news:[email protected]...
>> Tom Veatch wrote:
>>
>>> I agree it's a puzzle. I've failed so far to lay out an arrangement
>>> that can be cut with a table saw where the side not shown in your
>>> sketched plan view isn't full of gaps, voids, and/or mismatched edges.
>>
>> Good catch - I fired up DesignCAD and confess that I couldn't make the
>> geometry (as drawn) work either. Perhaps Dave is remembering another
>> joint...
>>
>> --
>> Morris Dovey
>> DeSoto Solar
>> DeSoto, Iowa USA
>> http://www.iedu.com/DeSoto/
>
> Actually, the second joint does work. I will post an AutoCAD sketch on
> ABPW. :-)
I was successful in posting a pdf of the joint. The joint needs to be
modified in order to fill the voids. That would be easy to do. I'm not sure
it could be done on a table saw.

The sketch shows a single part and then three parts assembled. And then I
showed a rotated view of the same assembly.

I think it is an ingenious solution.

On May 19, 8:55=A0am, Robatoy <[email protected]> wrote:
> On May 19, 8:46=A0am, RicodJour <[email protected]> wrote:
> > On May 19, 4:17=A0am, David Nebenzahl <[email protected]> wrote:
>
> > > Thanks. Since you like the design, you might find this variation
> > > interesting:
> http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.gif
>
> > > Came up with it while doodling designs for the tripod, but after maki=
ng
> > > a mock-up decided it was too much work for this project. I like the
> > > circular motif.
>
> > How would you assemble that joint? =A0It seems that you'd need fairly
> > loose fitting joinery and fairly thin pieces.
>
>
> Not to mention the amount of wasted material to make it (out of one
> piece)

Hmmm. You've given me an idea. Just scribe some lines on some wood
to make the joinery look complicated. Sure would be easier.

R

"Morris Dovey" <[email protected]> wrote in message
news:[email protected]...
> Tom Veatch wrote:
>
>> I agree it's a puzzle. I've failed so far to lay out an arrangement
>> that can be cut with a table saw where the side not shown in your
>> sketched plan view isn't full of gaps, voids, and/or mismatched edges.
>
> Good catch - I fired up DesignCAD and confess that I couldn't make the
> geometry (as drawn) work either. Perhaps Dave is remembering another
> joint...
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USA
> http://www.iedu.com/DeSoto/

Actually, the second joint does work. I will post an AutoCAD sketch on ABPW.
:-)

David Nebenzahl <[email protected]> wrote:

>On 5/18/2009 7:09 AM Morris Dovey spake thus:
>
>> I think the original joint was the truly ingenious one. So ingenious
>> that I've stashed it in my "must try" collection (even though I don't
>> build furniture).
>
>Thanks. Since you like the design, you might find this variation
>interesting:
>http://www.geocities.com/bonezphoto/wood/3-memberLapJointCir.gif
>
>Came up with it while doodling designs for the tripod, but after making
>a mock-up decided it was too much work for this project. I like the
>circular motif.
>
>Put that in your CNC program and smoke it!

I think that is structurally the same as your first joint, The shapes
of the lapped pieces are different, but otherwise it is the same
joint.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

"RicodJour" <[email protected]> wrote in message
news:71feef8c-32ca-4619-9e2b-3892fe115cfa@n21g2000vba.googlegroups.com...
On May 18, 10:09 am, Morris Dovey <[email protected]> wrote:
> Lowell Holmes wrote:
> > I was successful in posting a pdf of the joint. The joint needs to be
> > modified in order to fill the voids. That would be easy to do. I'm not
> > sure
> > it could be done on a table saw.
>
> Me too - but when I tried to do the modification (by shifting the
> "center" toward the side), I still couldn't make it work. I'm not
> certain that I couldn't have done better with another cup of coffee,
> but...

Obvious solution - get a bigger cup. ;)

R
I went to the shop and made a rough try at David's original joint. I had to
make a slight change from what my understanding is, but it did make up. The
work I did is rough and not close tolerance, but you can see the joint
works. I posted photos in abpw news group.

On Sun, 17 May 2009 17:27:20 -0700, David Nebenzahl
<[email protected]> wrote:

>While the original joint is stronger since it has a larger glue surface
>area, the new variant is much easier to make. In fact, I did the whole
>thing on the table saw, where in the original joint you have to chop out
>half of the waste. And I'm not the best wood-chopper-outer in the world,
>I'll admit. Hard to keep those surfaces flat enough for gluing.
>
>The new joint is an interesting little puzzle that I haven't completely
>figured out yet. Because of its asymmetry, it needs to be made oversize
>to cover the needed width. The finished joint looks nice, though not as
>interesting as the original with its angular inlets.


You say you've actually made the new variation of the joint using a
table saw? How about posting a picture or a dimensioned sketch of the
side not shown in the sketch in your link. A Sketch-Up model would be
preferred.

I agree it's a puzzle. I've failed so far to lay out an arrangement
that can be cut with a table saw where the side not shown in your
sketched plan view isn't full of gaps, voids, and/or mismatched edges.

Tom Veatch
Wichita, KS
USA

An armed society is a polite society.
Manners are good when one may have to back up his acts with his life.
Robert A. Heinlein