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Shoulder to cry on

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PerranOak

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Just had a crazy, destructive episode where I destroyed a tenon and its rail.

The problem was the maddening shoulder to and fro. One should was fine, the other had a bit of a gap. So, I shortened the fine one to match the other. I don't know how but then the situation was reversed! You can guess the rest- to and fro!

After I calmed down I realised that I often have this trouble. I use a chisel to tidy the shoulders which works most of the time to be honest but when it doesn't work it drives me crazy.

What is the BEST way to do the final shoulder tidy?

Please save my mental health.
 

Cheshirechappie

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When marking out the tenon, knife the shoulder line quite deeply all round the rail. That will cleanly sever the wood fibres. Saw the tenon by whatever hand or machine method you normally use, but make absolutely sure that you don't cut on the wrong side of the shoulder line. Then, on fitting the tenon, if you find a bit of waste still in place, click a chisel edge into the knifeline, and remove only that much.

If you are going to undercut, do so on the non-visible side of the joint. Arrange things so that you won't undercut on the face side, then the visible part of the joint on the finished job will be tight and clean.
 

PerranOak

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RogerP. Thanks for that. When undercutting, I can see that the faces will be flush but there will be a "V" shaped gap on the side of the rail, no?

Cheshirechappie. I did that, mostly. Darn! It must be my technique! I just thought that maybe one side is flush and the other not because the tenon is no 100% square. Could a shoulder plane help here?
 

RogerP

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PerranOak":3vuq84o5 said:
RogerP. Thanks for that. When undercutting, I can see that the faces will be flush but there will be a "V" shaped gap on the side of the rail, no?
Not if you undercut all the sides - not just the two long ones as shown it that video. It not a total answer, the rest has to be right first, but it can turn a good joint into an excellent one :)

As said by Cheshirechappie - knife the lines before you saw.
 

woodbloke

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I've always cut the shoulder lines using a chisel...the wider the better and as others have said, make sure that the line has been well marked with a knife. Provided that the bench is level in both planes (which mine is) you can cramp the wood down, place the chisel in the line (having first removed the cheeks with a saw) and sight it for plumb. Tap smartly down with a hammer (if using Jap chisels) to form a square shoulder, if it needs to be undercut a fraction then pare it vertically on the bench top...I wouldn't do it as shown in the clip and certainly not with a file or cabinet rasp - Rob
 

PerranOak

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Oh no. So you're saying I'm doing it right but I'm just not very good. :cry:

You're not wrong though!

What if the tenon is not quite vertical/at right angles?
 

RogerP

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PerranOak":3t2kpzet said:
Oh no. So you're saying I'm doing it right but I'm just not very good. :cry:
You're not wrong though!
What if the tenon is not quite vertical/at right angles?
That's why Festool Dominoes are so popular :) ... or just use loose tenons.
 

woodbloke

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PerranOak":3pq0stz9 said:
Oh no. So you're saying I'm doing it right but I'm just not very good. :cry:

You're not wrong though!

What if the tenon is not quite vertical/at right angles?
For many applications, probably most IMO, the tenon should be 'vertical', or in-line with the rail, which means that the shoulder line should be cut at right angles all the way round with the square on either face edge or side (for the lines to meet up). If the tenon isn't 'vertical' it means that your sawing is slightly skewed, but the shoulder lines shouldn't be affected by the sawing action...they should still be square and visible after the waste has been removed - Rob
 

PerranOak

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Rob, you're right, my sawing is always off!

What I do is to saw quite a way from the line then creep-up on it with a chisel. I think that this is when I go out-of-square.
 

Jacob

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Cheap n cheerful joinery way is first to push the rail in tight and square so that one shoulder is in contact (or one point on the shoulder if it isn't square itself).
Then saw down the gap on that shoulder with a tenon saw, which straightens out the sides. Make sure you don't saw through the tenon.
Then do same on the other shoulder. You have effectively equalized the gap between shoulder and stile on both sides so they should cramp up nicely. There may be some saw marks on the stile which might need sanding or filling , if they aren't to be covered by a panel moulding or something.
 

Cheshirechappie

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Rather than sawing away from the line when first cutting the tenon, it may be worth a bit of practicing on some scrap to get your tenon saw bang against the line. Set the saw so that one side of the kerf just 'halves' the knifeline, then set the end of your thumb against the side of the blade as a guide and support until the kerf is established - the knife will have severed the fibres, so the finish will be good. It can help to stop the saw jumping at the beginning of the cut if you 'take the weight off' - support the weight of the saw and imagine that you're just gliding the teeth over the surface of the wood. It sounds like a high skill, but if you try it on a bit of scrap you'll be amazed how fast it just becomes second nature. You'll soon be fitting 99 out of 100 tenons straight from the saw, with no need for paring to fit.

There's a three-part Youtube clip under 'sharpening a handsaw' or similar, the third part of which demonstrates tenon saw practice very nicely.
 

Mr T

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Hi

I would recommend sawing to the knife line. It may seem more accurate to fight shy of the line then pare back to it, but it never quite works out that way. It's worth doing a few practice cuts on a piece of scrap to get your eye in before cutting the tenon.

Check whether the joint is square by placing a ruler down the side before you try to correct the shoulders. Correcting an unsquare joint may also correct the should disparity, if your lucky!

Chris
 

Mr T

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