Tenon Shoulders

[Mike Burke]

I have been struggling with this problem for a while. Notice that the face shoulder is off set from the end shoulder. I don’t know what is causing it or how to fix it. I have been trying different ways with miter gauge , table saw sled. Using stops , checking stock for square all around but I can’t find the solution.This sample cut is with a regular saw blade, but I use a dado blade for my tenons.
Any suggestions, tips ? 473358

[Lee Schierer]

Looking at your photo is appears that three of the four cuts came out even. The fourth cut is off by a bit. There can be several causes. I would check the squareness of the original end cut to the narrow edge of the board. You should also measure the height of the tenon at each end of your long cuts. This will tell you how square your cuts are or aren't.

Is there any play at all between your miter gauge or sled and the miter slot? Any play in your stops. On fixed stops does any sawdust accumulate during cuts that might change your alignment?

[Joe Calhoon]

Shouldering tenons requires very square cuts at every operation. End of tenon for referencing the saw cut, the tenon itself, the saw fence needs to be square and hit the bump stop the same way every time. Any of these off and the shoulders will not be accurate.
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[Phil Gaudio]

I will sometimes clamp a stop block to my rip fence to gauge the tenon length. When the work piece is flat on the tables surface, it engages the stop block at the bottom of the block. When you rotate the work piece on edge to cut the small dimensions, the work piece will engage the stop block across a larger area. If the stop block or what its clamped to is not 90 degrees to the table surface, you could end up registering the work piece off a different spot on the stop block, which would give you the cut you are seeing. Hope that is close to clear.

[Ron Citerone]

Additionally, I have had more consistant result when I slow down the feed rate and concentrate on consistent downward pressure on the workpiece.

[Dave Zellers]

I usually have to deal with that too although your example is a bit more pronounced. Since my equipment is far from high end machinery, I eventually decided that's why Lee Valley makes shoulder planes. :D

I try to get a perfect set-up but almost always need to employ my medium shoulder plane. It's such a joy to use, I never mind. :)

[Andrew Seemann]

I just did that on some QSWO slats for a headboard and footboard. Same deal, I used the exact same setup for the shoulder cuts as the cheek cuts, doing one after another in fact.

I think I must slide the board over a 1/64" or so after I leave the stop. I wonder if it has to do with the the board being on its side and being awkward to hold compared to the cheek cut. Maybe I slide it slightly because I am holding it tighter to compensate for the awkward grip.

[Joe Calhoon]

If using the fence on a table saw for a stop on the shoulder cut a bump block works better as most fences have a little free cut to eliminate kick back and burning while ripping. If you are riding the fence for the stop you will get variation. With a bump stop you hit it the same way every time.

[Holmes Anderson]

That will happen because your reference surface, whether a flip stop or the fence, is not square with the table (horizontal to vertical). When you put the board on edge, it touches a different part of the fence or flip stop, changing the distance from the blade. The error increases with greater board width. If you have a hi/lo fence like a Unifence then use the low position. A No. 140 will clean up that shoulder in no time.

[Mike Burke]

Thanks for the reply's . It sounds like I'm not the only one that has this problem...that's some what of an encouragement.
I did check squareness of the stock on all sides and ends. I suppose that is going to make it crucial for perfect cuts. And I suppose the tall/wider the work piece the more that offset is going to be...depends on where it hits on the stop block.
It happens on both cheek cuts most of the time.
I have been trying it all different was with my stop setup
Against table saw fence, but if the fence is setup up toed out at the trailing end to prevent pinching then the work will follow the fence and get off set cuts. That was my first thought and so I checked my fence.
So I got our my miter gauge and used a stop block on the table saw fence and I also used a stop block on the tail end and didn't use the table saw fence at all. Then I noticed the the stop was taller than my work piece and as was mentioned the work piece was hitting at a different spot when stood up instead of laying flat so.....I used a this piece for a stop so the work piece only hit on a small area on thin stop. That helped a little.
Than I used my table saw sled with the same observation with the stop thickness's .....and still got a little offset with the check cuts.

I am going to try a bump stop like was mentioned earlier....with just a screw head for the bump spot.
Then I read a article in Fine Woodwork about this and they cut the cheek cuts close and finished them with a chisel. I have been doing that anyway trying to clean up the offset cut so guess its nothing new the wood working world.

I also have been under cutting the inner area next to the tenon so the outside area hits first instead of the area next to the tenon. I can see now why so many people use the floating tenon set up these days. A lot easier and quicker.

Anyway...Thanks for all the suggestions and tips. On with my struggle and trying to find a solution and setup that works for me.

[Mark e Kessler]

I agree with all of Joe’s comments, I always do a test cut on extra parts made at the same time, if every thing looks good on that test part and the issue comes up on the actual parts I first check all the parts to make sure everything is square if so then check my setup again in case something moved.

I found an issue once where i set up everything perfect with a .75” rail then did a 1.75” rail and it was off slightly, turns out it was the flipstop had a very slight angle to it which pushed the 1.75” piece further into the blade.

I have this issue I always start checking the squareness of everything,



i start with checking the wood par

[Mark Hennebury]

First; make sure that your stock is dressed flat, straight and square.

Flat; check on the jointer table, and check face to face.
Square faces; lay two lengths face to face on the jointer table, rotate and flip faces to confirm that they touch all combinations.
Square ends; Using the miter fence on you table saw, Trim 1/4" off the end of two long boards, then stand the boards on end face to face, rotate to confirm that they touch on opposite faces. This checks miters fences to travel, and blade to table squareness. This is critical to having shoulders co-planer, any error in miter fence angle will double when you flip from cutting the top to cutting the bottom faces.

Once you have confirmed that everything is flat, straight and square, procced as though it is not.

Put a stop on the miter fence outboard from the blade. The stop should be a piece of wood clamped to the miter fence, use a roundhead screw for the stop, the screw should be placed to reference in the middle of the stock that you are tenoning.
Placing the screw in the middle, assures that you board is referenced precisely the same distance from the blade, when you flip it over to cut the top or bottom, regardless of whether or not it is 100% square. The screw also allows you to make minute adjustments to line up the cut. This setup negates any referencing from different parts of an un-square end,

Cut tenons on one end of your stock only with this setup.

To cut the tenons on the other ends.
The stop should be on the outboard end, furthest away from the blade.
Move the stop to reference against the middle of the shoulder cut.
Cut the uncut ends.

This method ensures that you first end tenons are square and co-planer, and all of you second end tenons are the same distance shoulder to shoulder from the first ones. And negates any variation in length affecting shoulder to shoulder distance. Any variation in length will end up in tenon lengths on the second ends.

[Robert Engel]

I knife a line around, square referencing off 1 edge and 1 face. I cut the tenons about 1/32 shy and pare to the line.

Works every time!!

I usually use a miter gauge and stop block rather than a fence.

[Mike Burke]

Mark
Excellent instructions and process of procedure !!!
Thanks so much for all the details. The round head screw stop is exactly what I was thinking. I was heading that way by using a thinner / smaller stop in one of my methods. Excellent !!!
I am reassured that I will be getting better results from now on and that I am not the only one that has had or has this problem...and all the solutions , helpful tips I have received here.

Thanks so much