Tenon on 66" table apron

Dick wrote:>the way I cut tenon cheeks
>is to hold the piece vertically in a jig and run it through the TS, and this
>won't work for a 66" long piece of wood.

More than one way to go at it. Table saw set up with a dado, router, band saw,
or even a "cordless" saw (i.e. handsaw). HTH Tom

In article <[email protected]>,
Chris Merrill <[email protected]> wrote:
>Robert Bonomi wrote:
>> clamp a short piece (i.e. stops well _before_ getting to the blade) of stock
>> to the fence, such that the edge of the blade *AWAY* from the fence is the
>> required depth of the cheek. but the board up against that guide, and make
>> a pass over the blade. rotate board 180 degrees, and do other side. then
>> rotate 90 degrees to do one short edge, and another 180 to get the other
>> short edge.
>
>The board (e.g. stop block) clamped to the fence is not really necessary in
>this situation, is it? Since there is no 'cutoff', there is no loose piece
>to get kicked-back, right?
>
>If I understand kick-back correctly, you can run your board right up against
>the fence when you are _not_ making a through-cut. Anyone?

"Better safe than sorry" applies, when dealing with 'big' pieces.

With a *5-1/2*foot*long* board, there is a non-trivial risk of it 'twisting'
a bit, while riding against the miter guage.

If the board is butted up against the fence when this happens, it will
result in the board 'binding' between the fence and the blade.

With *UNPREDICTABLE* results. I'm sure you're familiar with Murphy's Law.
This is the kind of situation where _O'Brien's_Law_ comes into full play.
It states, simply, "Murphy was an *optimist*".

If the board is _not_ constrained against the fence, then it 'twists'
freely, and the -only- side-effect is a slightly widened kerf, and/or
maybe a little 'burning'. Essentially the board is free to move side-
to-side, that "very tiny amount" needed to minimize the blade contact
with the side of the cut.



Do you feel *LUCKY* today?? <grin>



Note: if the piece was only a couple of feet long, it'd be *much*easier*
to keep it 'tight' to the miter guage, and thus a 'greatly reduced'
risk of twist/bind.

30+ years ago, the shop teacher at my high school had a saying, that he
used with regularity:
"you've got to out-think the materials you work with".

*NOT* terribly flattering, when the 'materials' are a block of wood,
and he _intended_ it (mostly, anyway) along the lines of 'measure twice,
cut once', *but* it is a *very*valuable* precept with regards to shop
_safety_.

Anyway, there _were_ a fair number of kids in the class who -did- have
trouble 'out-thinking the materials'.

The facts remain,
(a) that the "inate animosity of inanimate objects" *is* a real force,
(b) if you don't give it a _chance_ to act, you're unlikely to be
surprised, and
(c) O'Brien is *always* looking over your shoulder, awaiting any
opportunity.

Robert Bonomi wrote:
> clamp a short piece (i.e. stops well _before_ getting to the blade) of stock
> to the fence, such that the edge of the blade *AWAY* from the fence is the
> required depth of the cheek. but the board up against that guide, and make
> a pass over the blade. rotate board 180 degrees, and do other side. then
> rotate 90 degrees to do one short edge, and another 180 to get the other
> short edge.

The board (e.g. stop block) clamped to the fence is not really necessary in
this situation, is it? Since there is no 'cutoff', there is no loose piece
to get kicked-back, right?

If I understand kick-back correctly, you can run your board right up against
the fence when you are _not_ making a through-cut. Anyone?

************************************
Chris Merrill
[email protected]
(remove the ZZZ to contact me)
************************************

On 08 Aug 2003, Dick Smith spake unto rec.woodworking:

> This is a long table for hobby work, surface is a 6' piece of
> countertop. I"m using a 5" wide apron all around, 66" long, which I
> hope is wide enough to prevent sagging, cornered with 2-1/4" legs. So
> how to join the apron pieces to the legs? I started to think M&T, but
> the way I cut tenon cheeks is to hold the piece vertically in a jig
> and run it through the TS, and this won't work for a 66" long piece of
> wood. Then I thought of using a hangar bolt through a diagonal brace
> at each corner (what's that joint called?). Finally I thought to use
> biscuits. But I still don't know which is best. Advice, please?
>
> Thanks ==> Dick
>

If you can support the apron pieces horizontally, perhaps with a
helping hand, you can cut the tenons with repeated passes over your
tablesaw blade. Set the fence to the depth of the tenon, the saw blade
to the thickness of the amount you want removed, and go to it. A bit slow,
but effective.

Biscuits are dandy if you need help edge gluing boards, but as a
mechanical joint on a 6' table that's going to see heavy use, they won't
last a week.

Saw them by hand, Dick. - it's not that hard to do. Mark out your joint
using a mortice gauge or marking gauge, knife in the shoulders deeply with a
craft knife. Run a blunt pencil over the gauge and knife marks. Because
the pencil is blunt, it won't go right into the cut, so it will leave two
parallel pencil marks like little rail tracks, one on either side of the
cut. You're aiming to remove the little line on the waste side of the cut,
and leave the little line on the good side. (This is called splitting the
line and is easier than it sounds with a good saw)

Put the apron in the vice at 45 degrees-ish and saw the diagonal of the
both cheek pieces. Flip the wood vertically and saw the other two diagonals
of the same tenon. Stand the apron in the vice vertically and saw
vertically downwards to the shoulder line - the two diagonal cuts you've
made already on each cheek will act as guides and give you a good accurate
cut.

Clamp the apron flat on the bench and make the shoulder cuts.

You can't beat M&T for a good strong leg joint. Forget biscuits and eschew
hardware.

Cheers

Frank




"Dick Smith" <[email protected]> wrote in message
news:[email protected]...
> This is a long table for hobby work, surface is a 6' piece of countertop.
> I"m using a 5" wide apron all around, 66" long, which I hope is wide
enough
> to prevent sagging, cornered with 2-1/4" legs. So how to join the apron
> pieces to the legs? I started to think M&T, but the way I cut tenon
cheeks
> is to hold the piece vertically in a jig and run it through the TS, and
this
> won't work for a 66" long piece of wood. Then I thought of using a hangar
> bolt through a diagonal brace at each corner (what's that joint called?).
> Finally I thought to use biscuits. But I still don't know which is best.
> Advice, please?
>
> Thanks ==> Dick
>
> --
> ****Email is dicksmith at charter dot net****
>
>

"Dick Smith" <[email protected]> wrote in message
news:[email protected]...
> This is a long table for hobby work, surface is a 6' piece of countertop.
> I"m using a 5" wide apron all around, 66" long, which I hope is wide
enough
> to prevent sagging, cornered with 2-1/4" legs. So how to join the apron
> pieces to the legs? I started to think M&T, but the way I cut tenon
cheeks
> is to hold the piece vertically in a jig and run it through the TS, and
this
> won't work for a 66" long piece of wood. Then I thought of using a hangar
> bolt through a diagonal brace at each corner (what's that joint called?).
> Finally I thought to use biscuits. But I still don't know which is best.
> Advice, please?
>
> Thanks ==> Dick
>
> --
> ****Email is dicksmith at charter dot net****
>
>
How about a router and jig. Do a google search for mortising jigs, or
router mortising jigs. The Dewalt website had a nice one that I use alot.
It works great. I would give you the URL, but my computer crashed 2 days
ago, and Im just getting back up. The nice thing with the router jig is it
doesnt matter how long your apron pieces are, as long as you can lay them
flat, you can affix the jig to them, and cut away. Good luck.


Drew

"Chris Merrill" <[email protected]> wrote in message
news:[email protected]...
> Robert Bonomi wrote:
> > clamp a short piece (i.e. stops well _before_ getting to the blade) of
stock
> > to the fence, such that the edge of the blade *AWAY* from the fence is
the
> > required depth of the cheek. but the board up against that guide,

>
> The board (e.g. stop block) clamped to the fence is not really necessary
in
> this situation, is it? Since there is no 'cutoff', there is no loose
piece
> to get kicked-back, right?
>
> If I understand kick-back correctly, you can run your board right up
against
> the fence when you are _not_ making a through-cut. Anyone?
>
> ************************************
> Chris Merrill

True. I'd be inclined to use the fence through the whole cut. I think it
would be helpful rather than harmful in this case.

-Jack

Another good example why it is a great idea to learn the use of hand tools.

--
Mike G.
Heirloom Woods
www.heirloom-woods.net
"Dick Smith" <[email protected]> wrote in message
news:[email protected]...
> This is a long table for hobby work, surface is a 6' piece of countertop.
> I"m using a 5" wide apron all around, 66" long, which I hope is wide
enough
> to prevent sagging, cornered with 2-1/4" legs. So how to join the apron
> pieces to the legs? I started to think M&T, but the way I cut tenon
cheeks
> is to hold the piece vertically in a jig and run it through the TS, and
this
> won't work for a 66" long piece of wood. Then I thought of using a hangar
> bolt through a diagonal brace at each corner (what's that joint called?).
> Finally I thought to use biscuits. But I still don't know which is best.
> Advice, please?
>
> Thanks ==> Dick
>
> --
> ****Email is dicksmith at charter dot net****
>
>

In article <[email protected]>,
Dick Smith <[email protected]> wrote:
>This is a long table for hobby work, surface is a 6' piece of countertop.
>I"m using a 5" wide apron all around, 66" long, which I hope is wide enough
>to prevent sagging, cornered with 2-1/4" legs. So how to join the apron
>pieces to the legs? I started to think M&T, but the way I cut tenon cheeks
>is to hold the piece vertically in a jig and run it through the TS, and this
>won't work for a 66" long piece of wood. Then I thought of using a hangar
>bolt through a diagonal brace at each corner (what's that joint called?).
>Finally I thought to use biscuits. But I still don't know which is best.
>Advice, please?

Got a dado blade?

You can do the cheeks as an 'overlapping' set of dado's.

clamp a short piece (i.e. stops well _before_ getting to the blade) of stock
to the fence, such that the edge of the blade *AWAY* from the fence is the
required depth of the cheek. but the board up against that guide, and make
a pass over the blade. rotate board 180 degrees, and do other side. then
rotate 90 degrees to do one short edge, and another 180 to get the other
short edge.

Now, pull the board back "most" of the width of the dado, and make another
4 passes.


repeat until you reach the end of the board.


Voila! *grin*

Note: the way this works is _exactly_ "backwards" to what you're used
to. You used the fence to determine the thickness of the cheek that
was being removed, and the height of the blade to determine how 'long'
the tennon was. With _this_ method, the fence determines how 'long'
the cheek is, and the height of the blade determines the thickness of
the cheek that is removed.

NOTE: if the cut-off is different on wide and narrow sides of the board,
do all the wide side 'overlapping' cuts first (both sides), *then* re-
adjust the blade height for the narrow-side shoulders, and proceed with
all the narrow side 'overlapping' cuts.


This is somewhat slower than doing the 'vertical' board, but lets you
manage with nearly _any_ size of rail.