Difficult Tenon Shoulder Made Easy

Today I needed to check whether the tenon shoulders of some curved stretchers were square .


This reminded me of a jig that Jeff Miller posted on his blog, which previewed a forthcoming article in Pop Wood magazine. This consists of a vise and a flush cutting saw (attached to the sole of a "plane").


Link: http://furnituremaking.com/wordpress/tenon-shoulders/


Jeff's jig:


http://i13.photobucket.com/albums/a2...ps472a834a.jpg


http://i13.photobucket.com/albums/a2...ps38eace0c.jpg


I needed this today. However it occurred to me that I already had one .... as do many of you as well.


"I do?", you ask. Yep .. it's your Moxon dovetail vise.


As long as the chop is aligned with the rear of the vise and has some width for regiistration, then you are good to go.


Line up the shoulder you know ...


http://i13.photobucket.com/albums/a2...psb136205f.jpg


Use a flush cutting saw to cut the opposing shoulder. This will be square with the first shoulder ...


http://i13.photobucket.com/albums/a2...ps686c724e.jpg


You can use a paring chisel if you only need to trim a little from an existing shoulder ...


http://i13.photobucket.com/albums/a2...ps34e43125.jpg


Done ...


http://i13.photobucket.com/albums/a2...ps365a0f3b.jpg


Regards from Perth


Derek

Quote:

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This reminded me of a jig that Jeff Miller posted on his blog, which previewed a forthcoming article in Pop Wood magazine.

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So many ways so little time...

That "forthcoming article" is in the February issue which is available for free download.

jtk

Thanks for the tip Derek.
Curious, what's the hinge on the back of your Moxon vise for?

If your tenon shoulders don't come out perfect off the saw(using a jig)then I don't see any advantage to using one.

Quote:

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Originally Posted by Judson Green

Thanks for the tip Derek.
Curious, what's the hinge on the back of your Moxon vise for?

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Here ya go Judson: http://www.inthewoodshop.com/ShopMad...rtheMoxon.html

Neat idea Derek. More and more uses for my moxon.

Quote:

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Originally Posted by Tony Wilkins

Here ya go Judson: http://www.inthewoodshop.com/ShopMad...rtheMoxon.html

Neat idea Derek. More and more uses for my moxon.

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Thanks Tony.

Quote:

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Originally Posted by Chris Vandiver

If your tenon shoulders don't come out perfect off the saw(using a jig)then I don't see any advantage to using one.

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Not meant to discredit or belittle the tenon tip Derek adapted or came up with, but I would not recommend this to beginners learning to saw or cut tenons, unless the intention is to use a hand tool just to tell people a hand tool has somehow been used rather than to learn the necessary skills and techniques to use the tool. Frankly, to cut perfect tenons, why not use the router/tablesaw and a jig?

Some of my students used a block to help guide a saw to cut straight and square down and I encouraged them not to...and by the end of the sawing class, those who took my advice had learned how to saw properly -- plumb, square, etc. Some would still need a block to guide their sawing.

It's ok to use a guide but that should be a training wheel and not a permanent way of doing certain things and in this case, cutting tenons.

Simon

Hi Simon

When I first saw Jeff's jig, my first reaction was "why in hell do we need that?"- all that is required is to score the shoulder, endercut it as a fence, and saw. No biggie - done this lots. And it develops hand memory.

However, the jig is not intended for straight stretchers/rails (although I can envisage some adapting it by adding a vertical fence). The jig is intended for curved stretchers/rails, where it is difficult to mark the opposing shoulders.

Regards from Perth

Derek

Thanks for the clarification, Derek.

Simon

Why is everyone calling this Jeff's jig, it is a copy of a very old french chair makers vise and saw.Attachment 279428

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Originally Posted by Tom McMahon

Why is everyone calling this Jeff's jig, it is a copy of a very old french chair makers vise and saw.Attachment 279428

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I was a bit confused as such by this; Jeff even discusses this fact in his article.

Quote:

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Originally Posted by Tom McMahon

Why is everyone calling this Jeff's jig, it is a copy of a very old french chair makers vise and saw.Attachment 279428

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Truer words have never been spoken. On the web there is someone putting their name to a centuries old process, tool, or practice every minute. It's really sad and shows a serious lack of depth and integrity.

Quote:

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Originally Posted by Derek Cohen

However, the jig is not intended for straight stretchers/rails (although I can envisage some adapting it by adding a vertical fence). The jig is intended for curved stretchers/rails, where it is difficult to mark the opposing shoulders.

Regards from Perth

Derek

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How can it be difficult to mark the opposing rail, but easy to jig a saw to it? Couldn't you just use that jig and then run a pencil along it? Obviously you still need the jig, but it would not be a massive jig that would have all the loads that thing deals with. I also sorta think if I knew this problem a little better I could come up with something soon enough. For one tihng, shoot a 20 or 30 thou stock in the first kerf and then make for it freehand, or just sight it and draw the line etc...

I have to say, I think a saw plane, once in the shop, might very well give rise to a million uses.

Quote:

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Originally Posted by Tom McMahon

Why is everyone calling this Jeff's jig, it is a copy of a very old french chair makers vise and saw.Attachment 279428

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For the same reason that The Bench is now called a Schwatz bench, and no longer a Roubo, though that is pretty reasonable, really...

It is an amateur woodworking rule that all past art is named after whoever first gets it into video or print. Sorta similar to how all modern music is copyrightable, but not to the benefit of the people who actually first penned it if they live a hundred or so years ago. I was thinking that maybe since copyright, at least for commercially valuable stuff, is essential for ever, that we should extend the rights regime to any descendants of people who may have a prior claim. Seems only fair.

I needed to check the shoulders again, was too lazy to pull out the Moxon vse fr this, looked around the workshop, and came up with this ...


http://i13.photobucket.com/albums/a2...ps4300559e.jpg


Surely everyone has a couple of wooden handscrew clamps?


Regards from Perth


Derek

Quote:

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Originally Posted by Derek Cohen

I needed to check the shoulders again, was too lazy to pull out the Moxon vse fr this, looked around the workshop, and came up with this ...


http://i13.photobucket.com/albums/a2...ps4300559e.jpg


Surely everyone has a couple of wooden handscrew clamps?


Regards from Perth


Derek

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Surprisingly when I pull mine out I've never met anyone in aus that had ever seen them before.

Quote:

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Originally Posted by Derek Cohen

I needed to check the shoulders again, was too lazy to pull out the Moxon vse fr this, looked around the workshop, and came up with this ...


http://i13.photobucket.com/albums/a2...ps4300559e.jpg


Surely everyone has a couple of wooden handscrew clamps?

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I've tried using my handscrew clamps for paring guides or runners for a router plane to ride on; the biggest difficulty in mine is getting both jaws to be co-planar; it's fidgety as heck, but that may very well be a side effect of the bargain-basement handscrew clamps I've got. (A couple of Stanleys I literally bought at a dollar store) Is this less of a hassle with some good handscrews?

HI Joshua

Here is a real example ..

My previous report on the chair build was aimed at determining the correct position for the mortice - and also whether the tenon shoulders were square across the upper and lower sides.


I had used templates to mark out the plan shape of each (front and rear) curved stretcher, however the shoulder angle of each tenon was gauged by eye. That is not the most reliable method (parallax and all that).


To my eye there was something definitely wrong.


I used the wooden hand screws to square up the shoulders. Here's how ...


Firstly, this is the curved stretcher (it is a compound curve, curving in two directions). There is no way one can simply use a square or even a sliding bevel to determine the square as there is no reference flat area.


http://i13.photobucket.com/albums/a2...psefe49d7b.jpg


If I was building a dedicated vise, the clamp/jaws would be narrow to minimise the effects of a curve. The hand screw here was sufficiently narrow for this task.


When clamped it made contact along both sides of each shoulder. You can see how much is to be removed.


http://i13.photobucket.com/albums/a2...psa4544b5b.jpg


Before sawing, ensure that both clamp sides are coplanar ...


http://i13.photobucket.com/albums/a2...ps01860df3.jpg


Now saw with a flush cutting saw (no set to damage the clamp) ..


http://i13.photobucket.com/albums/a2...ps337f64be.jpg


The tenon cheek was measured square to the shoulder on both sides ...


http://i13.photobucket.com/albums/a2...ps209ff154.jpg


Regards from Perth


Derek

Thanks for the pics, Derek. I hope I didn't sound like I was knocking the method, my concern was less whether it works (I've used something similar just enough to know it is) just how "fiddle-y" the set up of the clamp is. Obviously, like you show in the pick with the level, you need to make sure the jaws are co-planar, and this was the part that was always tough with my clamps; I guess I was just wondering if nicer ones (I kind of assume anything you have is nicer than anything I have ;) ) are less of a hassle to get aligned, or it's just a getting the touch down thing.

Enjoying watching this build, by the way.

Hi Joshua

It can be fiddly. I agree.

The method I found to work best is to first size the inner jaw (on the work piece), then get the jaws parallel, slide the clamp along the work piece, and tighten just enough that you can still adjust it with a tap of a hammer.

Regards from Perth

Derek