Tenons in riven stock

riven apron stock, joined stool

This photo is a section of white oak, riven and planed into apron stock for a joined stool I am making. The front,  true face is to our right, and the tenon is laid out from this face. The other day I was writing some text for the never-ending joined stool book Alexander & I are doing. The subject was cutting tenon shoulders in this sort of stock . In some cases, this stock is planed flat on its face, with two edges (mostly) square to this face, but with the back face left irregular and even unplaned.  Working with this tapered cross-section material can get confusing. To saw the front shoulder, the stock is sitting on its irregular rear face. This cants the stock a bit. It’s important to remember that the saw’s teeth should be parallel to the tenon line struck with the mortise gauge.

cutting front shoulder on riven stock

 

In this photo I enhanced the gauge lines with a pencil (some will know how it pains me to write that) so we can see what’s what. The stock is canted a bit, so the saw’s teeth should be as well. You have to think it through when you pick up the saw; the tendency is to saw with the teeth parallel to the workbench, which with squared-up stock is essentially the same as the teeth being parallel to the rail’s face.

It becomes simpler to see and feel when cutting the rear shoulder of this rail. Now the stock is laid on its front true face, thus it does sit flat on the wooden bench hook.  

riven apron stock, prior to cutting rear shoulder

 

But the rear face, where the saw enters the work, is quite canted. It’s easy to make a mistake and run the saw parallel to this irregular face…which would ruin the workpiece, by cutting into, or even through, the tenon. See how the teeth are parallel to the scribed lines, not to the surface of the stock.

cutting rear shoulder in riven stock

 

There’s lots more to the configuration of this tenon, but all I was after today was this point about the effects of the cross-section on layout and cutting. A small, but important point when working with riven stock.

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7 thoughts on “Tenons in riven stock

  1. Great pictures Peter, the book should be well worth waiting for.

    When cutting irregular shaped stuff like this, I have found it helpful to put a convenient packing piece under the rail to make the face side roughly horizontal when cutting its shoulder. The opposite rail, orientated the other way round sometimes does the job – if there is not too much of a twist in it. That way the saw can remain pretty much horizontal for all the cuts.

    Chris

  2. I was looking at the post about pegging the seat to the stiles on a previous joined stool, and was wondering why, as the board dries and shrinks, it doesn’t either work its way up the pegs or split. This kind of stuff has been giving me fits lately working in an unheated shop and then bringing the finished pieces into the house, though I have been working with air dried but commercially sawn boards and not riven stock.

    I stumbled across your site and blog relatively recently and am really happy I did. Definitely going to get the book hot of the presses. Have you found a publisher yet?

    Cheers, Brian

  3. Brian: You ask when pegging seats in place, why doesn’t the shrinking seat shrink up the pegs. Good question. First, it just doesn’t happen. In finished joinery, when all parts of the piece have reached e.m.c. (equivalent moisture content) the seat has shrunk down and the pegs are characteristically slightly proud. The seat’s thickness lies in the growth ring plane, the direction of maximum shrinkage. The pegs’ lengths lie in the direction of their woods’ long fibers. Shrinkage in this direction is virtually nil. The pegs are securely driven into the stools frame. The seat’s surface can only shrink down the pegs, the pegs stay where they are. Spooky, but true! I suspect Professor Follansbee will have more to post about this subject, together with pictures of peg projection. I’m looking forward to it. Perhaps, if possible, Peter would prefer to shift your Comment and this reply to his post about seat pegging.

  4. Thanks for the reply Jennie. I posted here because it was the latest and also had to do with the joined stools. First, I fully believe the pegs work just fine because obviously if they didn’t he would fasten the seats some other way.

    But the wood in the stool had been worked into fairly small pieces and was sitting around what looks like a heated shop for a while (and in any case like the pegs the rails are not going to shrink in length), while the seat had been recently split out and he wrote about the surface only recently having dried enough to finish smoothing the top. So one could expect some shrinkage in width, also, I would imagine, as the seat dried. I suspect that the answer is what you said about the shrinkage being mostly in the growth ring plane, that the seat is pretty narrow and just doesn’t shrink enough to matter.

    I went down and looked at a daybed/sofa I made a couple of years back. The stiles are quartersawn cherry and sure enough the pegs are sticking out quite a bit on the sides but are almost flush on the front of the stiles.

    I got into this when I got married and needed furniture – there was a pile of pasture oak sticked out in my father-in-law’s barn and it was mostly either that or Ikea. You read but sometimes stuff doesn’t sink in until you see it. Wonderful blog.

    Cheers, Brian

  5. Peter,

    Thanks for the great photos and info.

    I wonder if you could show the general timeline of assembly in a project like the joined stool that Brian and Jennie discussed above. The techniques and orientation of the wood planes make sense to me, but I am having a hard time visualizing when these parts should be assembled. How dry should the joints be to prevent splitting?

    There are times when you will work on a part, put it aside, then finish it later. I have read Jennie’s writing about fitting chair tenons into their mortises, and how they must be bone dry, yet the mortise can be “air dry.” Are there any such rules or timelines that you follow?

    Best regards,

    JJ

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