I must have read a thousand articles and looked at
many variations of jigs that produce a tenon.
I have never come up with a jig that I liked that
produced a tenon in a reasonable amount of time.
I always end up at the table saw with a miter guage
and a stop block.
Most of the time, I end up with a pretty fair tenon
but because of the amount of movement in the tablesaw
method, you can end up with a tenon that is not "exactly"
like all his brothers.
A good case in point is right now....
I'm building a coffee table for an aunt of mine.
She just had to have a "Mission Style" with all those
damn slats in the ends of the table.
That means 14 slats(7 per end) with 28 very small tenons.
The slat material is 1 1/8 " wide and 1/2" thick.
That means I end up with a very thin 1/4" tenon and very
small shoulders. It also means I need to cut 28 very small
mortises.
I keep thinking that there must be a router jig that is
suitable for this operation, but I don't seem to ever
find one(other than the Multirouter or Leigh M&T jig) that
would work for assembly line processing.
What do all the troops use for this operation ????
Make a router jig. I made a bed that had 42 slats for the head board and 42
for the food board, I also used the same jig for the siderails. I cut the
mortises with an attachment for my drill press. The slats were not glued
just a good fit.
Joe
"Pat Barber" <[email protected]> wrote in message
news:[email protected]...
> I must have read a thousand articles and looked at
> many variations of jigs that produce a tenon.
>
> I have never come up with a jig that I liked that
> produced a tenon in a reasonable amount of time.
>
> I always end up at the table saw with a miter guage
> and a stop block.
>
> Most of the time, I end up with a pretty fair tenon
> but because of the amount of movement in the tablesaw
> method, you can end up with a tenon that is not "exactly"
> like all his brothers.
>
> A good case in point is right now....
>
> I'm building a coffee table for an aunt of mine.
>
> She just had to have a "Mission Style" with all those
> damn slats in the ends of the table.
>
> That means 14 slats(7 per end) with 28 very small tenons.
>
> The slat material is 1 1/8 " wide and 1/2" thick.
>
> That means I end up with a very thin 1/4" tenon and very
> small shoulders. It also means I need to cut 28 very small
> mortises.
>
> I keep thinking that there must be a router jig that is
> suitable for this operation, but I don't seem to ever
> find one(other than the Multirouter or Leigh M&T jig) that
> would work for assembly line processing.
>
>
> What do all the troops use for this operation ????
>
>
>
>
>
>
I'm curious if you all glue in the spindles in your Mission style
projects since they don't seem to have any structural benefit.
Cleaning up glue seepage between spindles is a PIA.
I'm seriously considering just making the spindle mortise and tenons
tight but not glue them in. Is this a bad method??
Swingman wrote:
> "Pat Barber" wrote in message
>
> > Most of the time, I end up with a pretty fair tenon
> > but because of the amount of movement in the tablesaw
> > method, you can end up with a tenon that is not "exactly"
> > like all his brothers.
>
> > What do all the troops use for this operation ????
>
> You already know all this, but:
>
> Fasted method for tenons on mission style slats that I've been _ever_ been
> able to come up with is to bury a TS dado blade in a sacrificial fence and
> use the fence to set the length of the tenon, and the blade height the same
> for all four sides.
>
> I cut the 1/4" deep mortises with a hollow chisel mortiser, using whatever
> dimensions for mortise length results from the above ... on many "Mission"
> operations you just have to grin, bite the bullet and 'git r dun'.
>
> Also on A&C/Mission furniture you will often see the slats buried in a
> mortise, 1/4" deep, cut to the exact dimension of the slat, foregoing the
> cuting of tenons in thin stock completely.
>
> --
> www.e-woodshop.net
> Last update: 10/29/06
> Pat Barber wrote:
> >
> > What do all the troops use for this operation ????
Could you make round tenons?
Are your slats rectangular or square in cross section? I was assuming
square - in which case a round tenon or a loose dowel could be easier
than cutting square tenons. If rectangular, you could use 2
dowels/round tenons. If you had or bought a dowel cutter (i.e.
http://tinyurl.com/y9jmcp), and used a drill press with a jig/fixture
to hold the slats vertically, then drill the ends to make round tenons,
they could fit into holes drilled in the rails. Or drilling a hole
into the end of each slat, and one into the rail, would let you use
dowels (functionally loose tenons). You'd want to glue these at least
a tiny bit to keep the slats from spinning.
Good luck,
Andy
Can be routed and quite precisely.
Follow pix link to tenonmaker.
http://patwarner.com/images/index_tenon.jpg
******************************************
Pat Barber wrote:
> I must have read a thousand articles and looked at
> many variations of jigs that produce a tenon.
>
> I have never come up with a jig that I liked that
> produced a tenon in a reasonable amount of time.
>
> I always end up at the table saw with a miter guage
> and a stop block.
>
> Most of the time, I end up with a pretty fair tenon
> but because of the amount of movement in the tablesaw
> method, you can end up with a tenon that is not "exactly"
> like all his brothers.
>
> A good case in point is right now....
>
> I'm building a coffee table for an aunt of mine.
>
> She just had to have a "Mission Style" with all those
> damn slats in the ends of the table.
>
> That means 14 slats(7 per end) with 28 very small tenons.
>
> The slat material is 1 1/8 " wide and 1/2" thick.
>
> That means I end up with a very thin 1/4" tenon and very
> small shoulders. It also means I need to cut 28 very small
> mortises.
>
> I keep thinking that there must be a router jig that is
> suitable for this operation, but I don't seem to ever
> find one(other than the Multirouter or Leigh M&T jig) that
> would work for assembly line processing.
>
>
> What do all the troops use for this operation ????
A second option to what Jim suggested is to first make the full length
dado. You then cut a piece to fit the dado snugly. Cut dados across
is at the spacing required. I used this technique on a craftsman style
bed with 35 slats on head and foot boards. Of course you don't have
sholders on your slats with these methods
Jim Northey wrote:
>> Well how about a full length dado instead of separate mortises. Set your
> slats in and figure out the gaps then cut small spacer blocks to fill in the
> gaps. That's what I did on a sleigh bed I made a few years ago with curved
> slats. It might work for what your doing.
> Jim
I have used this method.. It is always a little
problematic getting the upper and lowers "just right"
but the method does work... That's a lot of parts
with wet glue trying to make it fit together.
Jim Northey wrote:
> Well how about a full length dado instead of separate mortises. Set your
> slats in and figure out the gaps then cut small spacer blocks to fill in the
> gaps.
That is much simpler than I would have thought.
The command structure don't look much worse than
some of the older macro languages I ran across
years ago.
Some things never change. Many of the "modern"
languages these younger guys are learning is just
a souped up version of the same old thing.
Prometheus wrote:
> G92 X50. Y50.
> [Tells the machine that the work area is 50" x 50"]
>
> M102(CRS0.125);
> [Recalls the library that contains the cutting conditions for the
> material, including Z-height, intensity, feed rate, pulse rate on
> corners, gas pressure and focus]
>
> G98 X.5 Y3.625 I2.25 J2.25 P2 K3;
> [Starts the canned cycle, and sets an individual origin point
> dedicated work area for each washer (I and J), P and K determine how
> many times the cycle should be repeated along the X and Y axis]
>
> M100;
> [Enables laser mode]
>
> U1;
> [Tells the machine to begin memorizing the canned cycle]
>
> G41;
> [Sets the kerf compensation to the left of the line defined by the
> program- this is assuming that the circle will be cut in a clockwise
> direction- if it were being cut counterclockwise, G42 would be
> selected]
>
> G00 X1.0 Y1.0;
> [Rapidly moves the head to the center of the washers to be cut,
> referenced to the changing origin point defined by the G98 command.]
>
> G112 X1.0 Y1.0 R.625 Q.08;
> [Recalls the circle cutting library, sets the center at (1,1), defines
> the circle has having a radius of 5/8" {note that in this case, this
> will make a hole that with a diameter of 5/8"- it's not really a true
> radius} The Q value tells the controller to start the lead-in cut
> .08" from the inside of the circle.]
>
> G112 X1.0 Y1.0 R2.0 Q-.08;
> [Recalls the circle cutting library, sets the center at (1,1), defines
> the circle as having a radius of 2 inches, and the Q value tells the
> controller to start the lead-in cut .08" from the outside of the
> circle {because it is a negative value}]
>
> M180;
> [Proprietary M-code to tell the work chute to cycle so that part will
> fall out of the sheet and into the collector]
>
> G00 M40;
> [Cancels modal G112 code, and cutter correction]
>
> M104;
> [Cancel cutting mode]
>
> V1;
> [Ends canned cycle]
>
> G75 U1 Q3 P1;
> [Canned cycle handling- G75 determines that the parts will be cut in a
> line along the X axis before moving the the next row in the Y axis-
> G76 means the opposite. U1 recalls the canned cycle defined between
> U1; and V1; Q3 defines the corner the cutting pattern will start in,
> and P1 tells it to start with the first part- if the cycle is
> interrupted, the P value can be altered to restart the cycle where it
> is needed]
>
> M101;
> [Laser mode off]
>
> G50;
> [Origins all axis]
>
> M00;
> [End program]
On Tue, 05 Dec 2006 15:21:29 GMT, Pat Barber
<[email protected]> wrote:
>I must have read a thousand articles and looked at
>many variations of jigs that produce a tenon.
>
>I have never come up with a jig that I liked that
>produced a tenon in a reasonable amount of time.
>
>I always end up at the table saw with a miter guage
>and a stop block.
>
>Most of the time, I end up with a pretty fair tenon
>but because of the amount of movement in the tablesaw
>method, you can end up with a tenon that is not "exactly"
>like all his brothers.
That's what I do, it's all about how carefully you set up. Granted,
the joints usually end up needing to be individually numbered and
worked for a perfect fit, but that is usually the fault of my chisel
work when excavating the mortises, not the tenons.
>A good case in point is right now....
>
>I'm building a coffee table for an aunt of mine.
>
>She just had to have a "Mission Style" with all those
>damn slats in the ends of the table.
>
>That means 14 slats(7 per end) with 28 very small tenons.
>
>The slat material is 1 1/8 " wide and 1/2" thick.
>
>That means I end up with a very thin 1/4" tenon and very
>small shoulders. It also means I need to cut 28 very small
>mortises.
Now here's an idea for you....
I know that mortise and tenon joints are great, and I use them a lot.
However, when I have done this, I have to confess that I use another
method. The guy that told me about it called it cheater's mortises.
Basically, you take the apron and the runner and cut a dado 1/2" wide
and an appropriate depth in each. Cut another piece of stock that is
1/2" wide, and mill out a series of grooves that are 1.125" wide with
the appropriate spacing between slats. Make one of these for each
dado. Those pieces should now look like a kid's drawing of a comb.
If you have cut carefully, you should be able to glue stock B into the
dadoes cut into the aprons and runners with a virtually invisible glue
line, leaving you with pieces that have the appearance of having been
perfectly mortised. Then, just slide the slats in without making
tenons. The nature of the dado and insert method should have left
clean enough "mortise" sides so that the shoulders aren't necessary to
hide imperfections, and your mechanical joints will still be in the
corners of the frame to act against racking forces.
It's not the purist approach, but it's a really slick compromise, and
it sure saves a lot of effort!
Pat Barber (in
[email protected]) said:
| I must have read a thousand articles and looked at
| many variations of jigs that produce a tenon.
|
| I have never come up with a jig that I liked that
| produced a tenon in a reasonable amount of time.
| What do all the troops use for this operation ????
Just remember that you /did/ ask...
Follow the link below for a look at how I cut /angled/ 1/4" tenons (in
1/4" hard maple stock) to /exactly/ fit a routed mortise using ~30
seconds/tenon.
Scroll to the bottom to see a stack of tenoned parts.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/Bevel.html
Pat Barber (in
[email protected]) said:
| I didn't forget and that is a very cool solution to
| a rather difficult problem. It never occurred to me that
| a CNC router couldn't actually cut any known angles without
| a little help.
|
| Not having ever seen a shopbot in person, I can now see that
| it really has no way to move the cutter head to any angle
| other than 90.(that may be a bad assumption)
|
| Are "all" your cuts in a flat bed position or can the cutter
| be positioned at other angles ???
The ShopBot's standard spindle is fixed perpendicular to the xy plane;
but it's possible to order up a rotating/tilting spindle head that
provides 5 degrees of freedom - but the cost of that head (alone) is
several times the cost of a standard 'Bot. I built a 4' wide clamp
across one end of the bot so that I could hold workpieces vertically
for dovetailing, etc (you can see the the handwheels that tighten the
clamp in one of the photos you saw); but I had a job that needed
tenons cut at odd angles and built the tilting fixture. Most of the
time I manage to get away with tilting the workpiece.
AFAICT the biggest challenge in CNC work is designing fixtures that
are both accurate and robust - and there are times when I have the
urge to hit the start button and run for cover. :-)
To get around the ShopBot 3-axis limitation, I've built another
(smaller, 3-1/2 axis) machine with a spindle that can be manually
tilted - and have been playing with a "next" machine that will place
the tilt under program control. You can get a quick look at my first
joinery machine by following the link in my sig.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/JBot.html
Pat Barber (in
[email protected]) said:
| I got to wondering about the "positioning" of the head of the
| router and what sort of software would be needed for that
| screwball math.
Not as complicated as you might think. There is an industry-standard
set of motion control commands that, in effect, allow the programmer
to say 'go to x y z'; where x, y, and z are the coordinates of the
endpoint of the motion. Typically x and y lie in the plane of the
table and z is a distance up or down from the table.
Math is handled pretty much as in any other programming language; and
I've found myself doing more trig than I ever expected - but very
seldom any math beyond what that covered in high school.
| I saw a full blown CNC setup at the IWF and
| I got to wondering how the guys made the head
| position it's self at a angle and the proper
| position overhead both north to south and east
| to west all at the same time.(very poor wording)
On a five-axis setup I would expect that the rotational position of
the head (azimuth) is an angular coordinate - and the tilt angle
(elevation?) just another angular coordinate.
| I know math is the answer but the machine must also
| "know" how big it's table is ??? Very neat stuff.
Maybe. My ShopBot doesn't know - but will refuse programmed commands
to move the spindle beyond boundaries (that I usually don't bother to
set).
| I have been a "business programmer" for over 30 years and
| don't have a clue about how CNC might even start to work.
'S not a big deal. A bit of programming background can't hurt (I
started programming in 1959 and made my living at it until 2001 - see
www.iedu.com/mrd/mrd_res1.html for a rundown) but isn't really
necessary.
| Is there certain CNC language for each machine, or do they
| use a generic version that works for everybody ???
Most modern machines use "G-Code" (I think there's a formal spec, but
can't remember its ID). The ShopBot uses a proprietary langauge; but
comes with a set of language converters which include a g-code
capability. The JBot's "native" language is g-code. I have a list of
g-code commands here somewhere - if you're interested I can e-mail a
copy.
| You do some very interesting stuff ....
I'm easily bored. If I didn't try new stuff from time to time, I'd go
nuts (not necessarily a far trip) 8-]
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
Pat Barber (in
[email protected]) said:
| I would like to see the short version of the instructions
| if it's not a lot of trouble.. My email works just as I
| post it....
On the way - wait.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
Prometheus (in [email protected]) said:
| Say Morris-
|
| I'm not very familiar with the ShopBot's design, but I know you've
| built one or two of the things. Did you ever consider stealing a
| page from the lathe, and put an indexing head on it between the
| motor mount and the Z-axis ways? It probably wouldn't lend itself
| to automation very easily, but might be more robust and accurate
| (and definately smaller) than a bunch of jigs for the parts being
| milled. I'd imagine you'd want to use screws to lock it in place
| rather than a sliding pin, but it might be an interesting way to
| solve the problem
It would be - and I have; but the right answer is to tilt the z-axis
ways themselves - which would require a complete re-design of the
gantry and y-axis. Tilting the spindle alone would require moving z-
and x-axis together during plunges; and as far as I can determine, the
'Bot doesn't have adequate precision to handle this at all tilt
angles. (The JBot does, but that's a whole different story.)
I /have/ seriously considered rebuilding the gantry; but without
metalworking equipment, I have doubts about doing it myself. If I
jobbed it out (in this area), it would be prohibitively expensive and
I'd need to worry about the quality of the result.
The problem is aggravated by the fact that the 'Bot already isn't as
rigid as I'd prefer; and by the fact that my 5HP/3-phase spindle is
capable of producing significant cutting forces. I already find myself
playing software games to avoid chatter marks on some cuts - and I
/really/ don't want to make the problem even a little worse.
But even if that problem were solved the fixturing problem just won't
go away. It seems to be a major consideration for every job - and
would be even if I could spring for the 5-axis head - because no
matter how well-controlled the spindle and cutter might be, the
_workpiece_ still wants to be "squirmy".
| If you're interested in the idea, I'm going to be making one for a
| Gingery lathe sometime in the next six months or so on the laser
| cutter at work and it would be fairly trivial to run an extra one
| once the program is loaded.
Thank you - it's a most generous offer - and if I had hopes that I
could make it work on the 'Bot, I'd take you up on it in a flash. I
hate to say no; but will because my machine isn't up to it.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto
On Wed, 06 Dec 2006 16:14:04 GMT, Pat Barber
<[email protected]> wrote:
>I have used this method on gardern benches and it works.
>
>It just requires more time to get that strip to fit just
>right and those dados cut just right.
>
>It does work... I was looking for a quicker method.
And making individual mortise and tenon joints is quicker? You're a
better man than I!
(BTW, sorry about re-describing the method before reading the whole
thread)
On Wed, 6 Dec 2006 14:45:49 -0600, "Morris Dovey" <[email protected]>
wrote:
>The ShopBot's standard spindle is fixed perpendicular to the xy plane;
>but it's possible to order up a rotating/tilting spindle head that
>provides 5 degrees of freedom - but the cost of that head (alone) is
>several times the cost of a standard 'Bot. I built a 4' wide clamp
>across one end of the bot so that I could hold workpieces vertically
>for dovetailing, etc (you can see the the handwheels that tighten the
>clamp in one of the photos you saw); but I had a job that needed
>tenons cut at odd angles and built the tilting fixture. Most of the
>time I manage to get away with tilting the workpiece.
Say Morris-
I'm not very familiar with the ShopBot's design, but I know you've
built one or two of the things. Did you ever consider stealing a page
from the lathe, and put an indexing head on it between the motor mount
and the Z-axis ways? It probably wouldn't lend itself to automation
very easily, but might be more robust and accurate (and definately
smaller) than a bunch of jigs for the parts being milled. I'd imagine
you'd want to use screws to lock it in place rather than a sliding
pin, but it might be an interesting way to solve the problem
If you're interested in the idea, I'm going to be making one for a
Gingery lathe sometime in the next six months or so on the laser
cutter at work and it would be fairly trivial to run an extra one once
the program is loaded.
>AFAICT the biggest challenge in CNC work is designing fixtures that
>are both accurate and robust - and there are times when I have the
>urge to hit the start button and run for cover. :-)
>
>To get around the ShopBot 3-axis limitation, I've built another
>(smaller, 3-1/2 axis) machine with a spindle that can be manually
>tilted - and have been playing with a "next" machine that will place
>the tilt under program control. You can get a quick look at my first
>joinery machine by following the link in my sig.
<[email protected]> wrote in message
> I'm curious if you all glue in the spindles in your Mission style
> projects since they don't seem to have any structural benefit.
>
> Cleaning up glue seepage between spindles is a PIA.
>
> I'm seriously considering just making the spindle mortise and tenons
> tight but not glue them in. Is this a bad method??
IMO, gluing slats is not necessary in most cases.
I've made/designed a good deal in this style and rarely glue in slats
unless, as in the case of a chair back, doing so would provide some
needed/additional structural integrity.
YMMV ...
--
www.e-woodshop.net
Last update: 10/29/06
Yep... I'll agree with that method also...
B A R R Y wrote:
> Pat Barber wrote:
>
>>
>> What do all the troops use for this operation ????
>>
>
> A table saw a crosscut SLED, and stop blocks. Miter gages are evil.
>
> I cut them slightly fat (~ 1/64 - 1/32) and perfect each fit with a
> shoulder plane at dry fit.
>
In article <[email protected]>,
Pat Barber <[email protected]> wrote:
>I must have read a thousand articles and looked at
>many variations of jigs that produce a tenon.
>
>I have never come up with a jig that I liked that
>produced a tenon in a reasonable amount of time.
>
>I always end up at the table saw with a miter guage
>and a stop block.
>
>Most of the time, I end up with a pretty fair tenon
>but because of the amount of movement in the tablesaw
>method, you can end up with a tenon that is not "exactly"
>like all his brothers.
>
>A good case in point is right now....
>
>I'm building a coffee table for an aunt of mine.
>
>She just had to have a "Mission Style" with all those
>damn slats in the ends of the table.
>
>That means 14 slats(7 per end) with 28 very small tenons.
>
>The slat material is 1 1/8 " wide and 1/2" thick.
>
>That means I end up with a very thin 1/4" tenon and very
>small shoulders. It also means I need to cut 28 very small
>mortises.
>
>I keep thinking that there must be a router jig that is
>suitable for this operation, but I don't seem to ever
>find one(other than the Multirouter or Leigh M&T jig) that
>would work for assembly line processing.
>
>
>What do all the troops use for this operation ????
>
>
>
>
>
>
I don't know about the rest of the troops, but personally I use a
single groove 1/2" thick long engough for _all_ the slats to fit in,
no tenons needed, and shoot a brad or 2 through the back side if necessary.
--
For every complicated, difficult problem, there is a simple, easy
solution that does not work.
Larry Wasserman - Baltimore Maryland - [email protected]
I would like to see the short version of the instructions
if it's not a lot of trouble.. My email works just as I
post it....
Morris Dovey wrote:
> Pat Barber (in
> [email protected]) said:
>
> | I got to wondering about the "positioning" of the head of the
> | router and what sort of software would be needed for that
> | screwball math.
>
> Not as complicated as you might think. There is an industry-standard
> set of motion control commands that, in effect, allow the programmer
> to say 'go to x y z'; where x, y, and z are the coordinates of the
> endpoint of the motion. Typically x and y lie in the plane of the
> table and z is a distance up or down from the table.
>
> Math is handled pretty much as in any other programming language; and
> I've found myself doing more trig than I ever expected - but very
> seldom any math beyond what that covered in high school.
>
> | I saw a full blown CNC setup at the IWF and
> | I got to wondering how the guys made the head
> | position it's self at a angle and the proper
> | position overhead both north to south and east
> | to west all at the same time.(very poor wording)
>
> On a five-axis setup I would expect that the rotational position of
> the head (azimuth) is an angular coordinate - and the tilt angle
> (elevation?) just another angular coordinate.
>
> | I know math is the answer but the machine must also
> | "know" how big it's table is ??? Very neat stuff.
>
> Maybe. My ShopBot doesn't know - but will refuse programmed commands
> to move the spindle beyond boundaries (that I usually don't bother to
> set).
>
> | I have been a "business programmer" for over 30 years and
> | don't have a clue about how CNC might even start to work.
>
> 'S not a big deal. A bit of programming background can't hurt (I
> started programming in 1959 and made my living at it until 2001 - see
> www.iedu.com/mrd/mrd_res1.html for a rundown) but isn't really
> necessary.
>
> | Is there certain CNC language for each machine, or do they
> | use a generic version that works for everybody ???
>
> Most modern machines use "G-Code" (I think there's a formal spec, but
> can't remember its ID). The ShopBot uses a proprietary langauge; but
> comes with a set of language converters which include a g-code
> capability. The JBot's "native" language is g-code. I have a list of
> g-code commands here somewhere - if you're interested I can e-mail a
> copy.
>
> | You do some very interesting stuff ....
>
> I'm easily bored. If I didn't try new stuff from time to time, I'd go
> nuts (not necessarily a far trip) 8-]
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USA
> http://www.iedu.com/DeSoto
>
>
I didn't forget and that is a very cool solution to
a rather difficult problem. It never occurred to me that
a CNC router couldn't actually cut any known angles without
a little help.
Not having ever seen a shopbot in person, I can now see that
it really has no way to move the cutter head to any angle
other than 90.(that may be a bad assumption)
Are "all" your cuts in a flat bed position or can the cutter
be positioned at other angles ???
Morris Dovey wrote:
> Pat Barber (in
> [email protected]) said:
>
> | I must have read a thousand articles and looked at
> | many variations of jigs that produce a tenon.
> |
> | I have never come up with a jig that I liked that
> | produced a tenon in a reasonable amount of time.
>
> | What do all the troops use for this operation ????
>
> Just remember that you /did/ ask...
>
> Follow the link below for a look at how I cut /angled/ 1/4" tenons (in
> 1/4" hard maple stock) to /exactly/ fit a routed mortise using ~30
> seconds/tenon.
>
> Scroll to the bottom to see a stack of tenoned parts.
>
> --
> Morris Dovey
> DeSoto Solar
> DeSoto, Iowa USA
> http://www.iedu.com/DeSoto/Bevel.html
>
>
Pat Barber wrote:
> I must have read a thousand articles and looked at
> many variations of jigs that produce a tenon.
>
> I have never come up with a jig that I liked that
> produced a tenon in a reasonable amount of time.
>
> I always end up at the table saw with a miter guage
> and a stop block.
Either that or use a jig and make a cheek cut.
Probably worth the set up for 28 tenons.
Sorry, but IMHO, not a router operation.
Lew
<[email protected]> wrote in message
news:[email protected]...
> Can be routed and quite precisely.
> Follow pix link to tenonmaker.
> http://patwarner.com/images/index_tenon.jpg
The devil here is consistency. As the other Pat has mentioned, he has
problems getting the tenons consistent in length with his dado. Router jigs
do this just fine, which places a premium on getting the slats all the same
length originally, so they will ultimately be the same _between the
shoulders_ .
With the recent project I had a mess of non-structural slats which I
hammered into routed pockets. I also had some places where they were
structural. For those areas I mortised down another 1/2 x 7/8 x 1" at each
pocket so I could glue and pin a conventional tenon.
To get the slats the same between shoulders, I made the tenons on one end
first with the conventional miter gage/stop block against the fence setup
after squaring the end. Depth of tenon my concern. I then set the shoulder
to shoulder distance on a stop block on my miter gage jig, referenced it to
the shoulder I had created, not the bottom of the tenon as I formed the
shoulder at the other end. Didn't care how long the tenon was, as long as it
was enough to be pegged. I then raised the blade and cut the long "loose
tenons" to length using the same setup, referencing the squared end to the
same stop I had used for the shoulder. Trimmed long tenons as required so
as not to bottom in the mortises later.
If I thought I could match the "rounded end" left by
the router bit, I would almost certainly use this
method...
I use loose tenons for almost all my M&T stuff.
I prefer the router over all other methods.
George wrote:
> How about changing your thoughts to what we call a loose tenon? Your
> slats are 1/2" bullnosed, or 3/8, your choice, very long tenons, and the
> mortises are cut with a plunge router and jig for desired spacing.
> Stuff 'em in, and you can even go without glue if you care. You have
> top and bottom rails to maintain distance.
>
>
On Mon, 11 Dec 2006 15:54:39 GMT, Pat Barber
<[email protected]> wrote:
>That is much simpler than I would have thought.
Yep. I figured a sample would make that clear. It looks like a lot
when you're just eyeing up a list of codes without context, but the
logic is very basic when it's in context.
>The command structure don't look much worse than
>some of the older macro languages I ran across
>years ago.
No, it's fairly straight forward, and it's been in use for quite a
while- so it may even be a slightly modified contemporary of the macro
languages you remember.
>Some things never change. Many of the "modern"
>languages these younger guys are learning is just
>a souped up version of the same old thing.
Most things never change, we just tell one another they have.
> I'm curious if you all glue in the spindles in your Mission style
> projects since they don't seem to have any structural benefit.
>
> Cleaning up glue seepage between spindles is a PIA.
Just put glue the mortise, not the tennon. Make the mortise a little deep.
any extra glue will end up at the bottom of the mortise.
In all M&T glue-ups I always apply glue very sparingly to the tennon, but I
am more generous on the mortise.
Squeezeout is next to nothing.
-Steve
"Pat Barber" <[email protected]> wrote in message
news:[email protected]...
> If I thought I could match the "rounded end" left by
> the router bit, I would almost certainly use this
> method...
>
> I use loose tenons for almost all my M&T stuff.
>
> I prefer the router over all other methods.
>
> George wrote:
>
>
>> How about changing your thoughts to what we call a loose tenon? Your
>> slats are 1/2" bullnosed, or 3/8, your choice, very long tenons, and the
>> mortises are cut with a plunge router and jig for desired spacing. Stuff
>> 'em in, and you can even go without glue if you care. You have top and
>> bottom rails to maintain distance.
>>
If I can with fifty-two on this latest project, you can, I'm sure.
I have used this method on gardern benches and it works.
It just requires more time to get that strip to fit just
right and those dados cut just right.
It does work... I was looking for a quicker method.
Mike in Arkansas wrote:
> A second option to what Jim suggested is to first make the full length
> dado. You then cut a piece to fit the dado snugly. Cut dados across
> is at the spacing required. I used this technique on a craftsman style
> bed with 35 slats on head and foot boards. Of course you don't have
> sholders on your slats with these methods
"Pat Barber" <[email protected]> wrote in message
news:[email protected]...
>
> I'm building a coffee table for an aunt of mine.
>
> She just had to have a "Mission Style" with all those
> damn slats in the ends of the table.
>
> That means 14 slats(7 per end) with 28 very small tenons.
>
> The slat material is 1 1/8 " wide and 1/2" thick.
>
> That means I end up with a very thin 1/4" tenon and very
> small shoulders. It also means I need to cut 28 very small
> mortises.
>
> I keep thinking that there must be a router jig that is
> suitable for this operation, but I don't seem to ever
> find one(other than the Multirouter or Leigh M&T jig) that
> would work for assembly line processing.
>
>
> What do all the troops use for this operation ????
>
How about changing your thoughts to what we call a loose tenon? Your slats
are 1/2" bullnosed, or 3/8, your choice, very long tenons, and the mortises
are cut with a plunge router and jig for desired spacing. Stuff 'em in, and
you can even go without glue if you care. You have top and bottom rails to
maintain distance.
"Pat Barber" <[email protected]> wrote in message
news:[email protected]...
>I must have read a thousand articles and looked at
> many variations of jigs that produce a tenon.
>
> I have never come up with a jig that I liked that
> produced a tenon in a reasonable amount of time.
>
> I always end up at the table saw with a miter guage
> and a stop block.
>
> Most of the time, I end up with a pretty fair tenon
> but because of the amount of movement in the tablesaw
> method, you can end up with a tenon that is not "exactly"
> like all his brothers.
>
> A good case in point is right now....
>
> I'm building a coffee table for an aunt of mine.
>
> She just had to have a "Mission Style" with all those
> damn slats in the ends of the table.
>
> That means 14 slats(7 per end) with 28 very small tenons.
>
> The slat material is 1 1/8 " wide and 1/2" thick.
>
> That means I end up with a very thin 1/4" tenon and very
> small shoulders. It also means I need to cut 28 very small
> mortises.
>
> I keep thinking that there must be a router jig that is
> suitable for this operation, but I don't seem to ever
> find one(other than the Multirouter or Leigh M&T jig) that
> would work for assembly line processing.
>
>
> What do all the troops use for this operation ????
Well how about a full length dado instead of separate mortises. Set your
slats in and figure out the gaps then cut small spacer blocks to fill in the
gaps. That's what I did on a sleigh bed I made a few years ago with curved
slats. It might work for what your doing.
Jim
I got to wondering about the "positioning" of the head of the
router and what sort of software would be needed for that
screwball math.
I saw a full blown CNC setup at the IWF and
I got to wondering how the guys made the head
position it's self at a angle and the proper
position overhead both north to south and east
to west all at the same time.(very poor wording)
I know math is the answer but the machine must also
"know" how big it's table is ??? Very neat stuff.
I have been a "business programmer" for over 30 years and
don't have a clue about how CNC might even start to work.
Is there certain CNC language for each machine, or do they
use a generic version that works for everybody ???
You do some very interesting stuff ....
Morris Dovey wrote:
> AFAICT the biggest challenge in CNC work is designing fixtures that
> are both accurate and robust - and there are times when I have the
> urge to hit the start button and run for cover. :-)
>
> To get around the ShopBot 3-axis limitation, I've built another
> (smaller, 3-1/2 axis) machine with a spindle that can be manually
> tilted - and have been playing with a "next" machine that will place
> the tilt under program control. You can get a quick look at my first
> joinery machine by following the link in my sig.
On Sun, 10 Dec 2006 09:04:42 -0600, "Morris Dovey" <[email protected]>
wrote:
>Prometheus (in [email protected]) said:
>
>| Say Morris-
>|
>| I'm not very familiar with the ShopBot's design, but I know you've
>| built one or two of the things. Did you ever consider stealing a
>| page from the lathe, and put an indexing head on it between the
>| motor mount and the Z-axis ways? It probably wouldn't lend itself
>| to automation very easily, but might be more robust and accurate
>| (and definately smaller) than a bunch of jigs for the parts being
>| milled. I'd imagine you'd want to use screws to lock it in place
>| rather than a sliding pin, but it might be an interesting way to
>| solve the problem
>
>It would be - and I have; but the right answer is to tilt the z-axis
>ways themselves - which would require a complete re-design of the
>gantry and y-axis. Tilting the spindle alone would require moving z-
>and x-axis together during plunges; and as far as I can determine, the
>'Bot doesn't have adequate precision to handle this at all tilt
>angles. (The JBot does, but that's a whole different story.)
Gotcha. That is the way I've seen it done in the past (with the
entire ways tilting), and probably why I have not seen a divider head
used.
>I /have/ seriously considered rebuilding the gantry; but without
>metalworking equipment, I have doubts about doing it myself. If I
>jobbed it out (in this area), it would be prohibitively expensive and
>I'd need to worry about the quality of the result.
Yep- that's a big job. For your consideration, I've seen a fair
amount of industrial metalworking equipment made with layers of sheet
material cut and then welded into stacks to make the larger parts. If
you ever do decide to tackle it, you might get by with a cutting
torch, a welder, a grinder and a whole lot of determination. Probably
not worth the effort financially- but sometimes it's not just about
that.
>Thank you - it's a most generous offer - and if I had hopes that I
>could make it work on the 'Bot, I'd take you up on it in a flash. I
>hate to say no; but will because my machine isn't up to it.
No problem. After seeing your reply, it certainly does make sense not
to go that route. It's a possibility that the divider would work at
the bottom of the gantry, but that would need to be much larger than
the one I'll be making, and probably far too unwieldy to make much
sense.
On Wed, 6 Dec 2006 16:32:16 -0600, "Morris Dovey" <[email protected]>
wrote:
>Pat Barber (in
>[email protected]) said:
>
>| I got to wondering about the "positioning" of the head of the
>| router and what sort of software would be needed for that
>| screwball math.
>
>Not as complicated as you might think. There is an industry-standard
>set of motion control commands that, in effect, allow the programmer
>to say 'go to x y z'; where x, y, and z are the coordinates of the
>endpoint of the motion. Typically x and y lie in the plane of the
>table and z is a distance up or down from the table.
>
>Math is handled pretty much as in any other programming language; and
>I've found myself doing more trig than I ever expected - but very
>seldom any math beyond what that covered in high school.
It gets even easier with g-code standard programming. The words are
essentially libraries that are modified by the arguments. So to make,
for instance, a circle, you don't even need to know the math involved-
a sample line would just look like this-
G112 X0.563 Y1.225 R0.625;
Where G112 calls the circle subroutine, the X and Y set the center of
the circle, and R sets the radius. G41/G42 on a previous line set the
cutterhead correction to right or left side of the line.
Trig is useful to an extent, but not absolutely necessary if a guy is
using CAM to generate G-codes. It's not even strictly necessary if
you manually draft the part on graph paper.
>
>| I know math is the answer but the machine must also
>| "know" how big it's table is ??? Very neat stuff.
>
>Maybe. My ShopBot doesn't know - but will refuse programmed commands
>to move the spindle beyond boundaries (that I usually don't bother to
>set).
The standard commands I use define the table size with G92, so it does
"know" how big the table is. The G92 command defines the upper left
corner of the work area, and the origin point defines the lower right
corner. There are set boundries as well, but it can't position itself
properly without that G92 line in place.
>| I have been a "business programmer" for over 30 years and
>| don't have a clue about how CNC might even start to work.
>
>'S not a big deal. A bit of programming background can't hurt (I
>started programming in 1959 and made my living at it until 2001 - see
>www.iedu.com/mrd/mrd_res1.html for a rundown) but isn't really
>necessary.
>
>| Is there certain CNC language for each machine, or do they
>| use a generic version that works for everybody ???
>
>Most modern machines use "G-Code" (I think there's a formal spec, but
>can't remember its ID). The ShopBot uses a proprietary langauge; but
>comes with a set of language converters which include a g-code
>capability. The JBot's "native" language is g-code. I have a list of
>g-code commands here somewhere - if you're interested I can e-mail a
>copy.
There is a standardized spec, but most machines have a few specialized
words like the G112 example above- to do the same thing with standard
codes, you'd need to set an arc or two using G02 or G03.
Here's a link to the how it all works- it's actually pretty easy once
you get the basic idea.
http://www.linuxcnc.org/handbook/gcode/g-code.html
If that's a bit thick, here's a sample of what a simple laser cutter
program might look like to cut a 12 washers from a sheet of 11ga.
steel.
// Washer program, makes a washer 2" in dia. with a 5/8" hole
G92 X50. Y50.
[Tells the machine that the work area is 50" x 50"]
M102(CRS0.125);
[Recalls the library that contains the cutting conditions for the
material, including Z-height, intensity, feed rate, pulse rate on
corners, gas pressure and focus]
G98 X.5 Y3.625 I2.25 J2.25 P2 K3;
[Starts the canned cycle, and sets an individual origin point
dedicated work area for each washer (I and J), P and K determine how
many times the cycle should be repeated along the X and Y axis]
M100;
[Enables laser mode]
U1;
[Tells the machine to begin memorizing the canned cycle]
G41;
[Sets the kerf compensation to the left of the line defined by the
program- this is assuming that the circle will be cut in a clockwise
direction- if it were being cut counterclockwise, G42 would be
selected]
G00 X1.0 Y1.0;
[Rapidly moves the head to the center of the washers to be cut,
referenced to the changing origin point defined by the G98 command.]
G112 X1.0 Y1.0 R.625 Q.08;
[Recalls the circle cutting library, sets the center at (1,1), defines
the circle has having a radius of 5/8" {note that in this case, this
will make a hole that with a diameter of 5/8"- it's not really a true
radius} The Q value tells the controller to start the lead-in cut
.08" from the inside of the circle.]
G112 X1.0 Y1.0 R2.0 Q-.08;
[Recalls the circle cutting library, sets the center at (1,1), defines
the circle as having a radius of 2 inches, and the Q value tells the
controller to start the lead-in cut .08" from the outside of the
circle {because it is a negative value}]
M180;
[Proprietary M-code to tell the work chute to cycle so that part will
fall out of the sheet and into the collector]
G00 M40;
[Cancels modal G112 code, and cutter correction]
M104;
[Cancel cutting mode]
V1;
[Ends canned cycle]
G75 U1 Q3 P1;
[Canned cycle handling- G75 determines that the parts will be cut in a
line along the X axis before moving the the next row in the Y axis-
G76 means the opposite. U1 recalls the canned cycle defined between
U1; and V1; Q3 defines the corner the cutting pattern will start in,
and P1 tells it to start with the first part- if the cycle is
interrupted, the P value can be altered to restart the cycle where it
is needed]
M101;
[Laser mode off]
G50;
[Origins all axis]
M00;
[End program]
This is kind of a "Hello world" program for a CNC machine, but it
should give you some idea of what is going on. It might look a little
daunting, but it's really a very high-level programming language and
requires little more than a list of the codes and the ability to
visualize spatial relationships. CNC Routers, mills and lathes work
in much the same way, though the arguments that follow the words will
vary depending on the machine. I just used the laser cutter as an
example becuase I set the thing up several times a day, and it's what
I'm most used to right now.
On 5 Dec 2006 08:46:10 -0800, [email protected] wrote:
>I'm curious if you all glue in the spindles in your Mission style
>projects since they don't seem to have any structural benefit.
>
>Cleaning up glue seepage between spindles is a PIA.
>
>I'm seriously considering just making the spindle mortise and tenons
>tight but not glue them in. Is this a bad method??
Not at all, IMO- I don't, for the very reason you mention, and it's
never been a problem- even in the bench that sits outside year round
and is exposed to the entire range of Wisconsin's weather (Hot and
humid in the summer to dry and frigid in the winter)
"Pat Barber" wrote in message
> Most of the time, I end up with a pretty fair tenon
> but because of the amount of movement in the tablesaw
> method, you can end up with a tenon that is not "exactly"
> like all his brothers.
> What do all the troops use for this operation ????
You already know all this, but:
Fasted method for tenons on mission style slats that I've been _ever_ been
able to come up with is to bury a TS dado blade in a sacrificial fence and
use the fence to set the length of the tenon, and the blade height the same
for all four sides.
I cut the 1/4" deep mortises with a hollow chisel mortiser, using whatever
dimensions for mortise length results from the above ... on many "Mission"
operations you just have to grin, bite the bullet and 'git r dun'.
Also on A&C/Mission furniture you will often see the slats buried in a
mortise, 1/4" deep, cut to the exact dimension of the slat, foregoing the
cuting of tenons in thin stock completely.
--
www.e-woodshop.net
Last update: 10/29/06
I have given this method serious thought
Swingman wrote:
Yep...this is my current method...
> I cut the 1/4" deep mortises with a hollow chisel mortiser, using whatever
> dimensions for mortise length results from the above ... on many "Mission"
> operations you just have to grin, bite the bullet and 'git r dun'.
I did give this method very serious consideration.
If I could come up with a round over that matched the router
bit, I think that would be the way to go with these slats.
I use a mortising machine but it will not produce a really
crisp edge that I would care for. I much prefer the router
for making my mortises.
>
> Also on A&C/Mission furniture you will often see the slats buried in a
> mortise, 1/4" deep, cut to the exact dimension of the slat, foregoing the
> cuting of tenons in thin stock completely.
>