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For a craftsman-style table, I'd like to shorten the stubs to refine the look of the table.

Would driving one or two dowels (blue outline in image) across the tenon allow for a smaller, but equally strong, stub? I'm thinking that could increase the surface of grain that would need to fracture in order for the joint to fail.

If I inserted them along the wedge line, it could also provide a helpful guide when carving the mortise.

I haven't seen any furniture examples of this (yet).

dowel (tenon shape is square, 1 1/8" x 1 1/8". wedge is 3/8" wide).

edit Missing detail: the grain in the tenon runs horizontal (topleft-to-bottomright in the photo), perpendicular to the tusk.

  • Depending on the longitudinal grain running into the tenon this may not really be necessary, i.e. if it's not vertical (aligned with the tusk) there's less risk, if it's actually diagonal there's unlikely to be a problem. But you lose nothing making it stronger in this way if you want to so go for it. – Graphus Jun 18 '18 at 12:00
  • If you're interested in a similar joint that avoids this issue, and looks more elegant too IMO, you can do the mortise sideways through the tenon and then use a pair of wedges (folding wedges) driven in from both sides, see here in Gary Rogowski's book on joinery. You can do much the same thing with a drilled hole and two portions of dowel although sawing those dowel wedges can be more challenging. And if you scroll up to page 371 in the book preview there's one other option you mike like — the wedged-through-dovetail tenon. – Graphus Jun 18 '18 at 12:17
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Yes, you can absolutely do this. I did it in one project as you can see in the second picture of this project.

enter image description here

It basically does what you said - increases fracture toughness of the small stub of a tusk tenon by:

  1. increasing glued surface area, and
  2. adding some cross-grain strength to a short section.
  • Nice shelves Aaron. Where do you think increased glue surface area comes into this? – Graphus Jun 20 '18 at 11:33
  • thanks! it's basic composites theory... if a crack were to propagate across the dowel, it would need to either go through the dowel or around it. If the dowel is really strong (imagine it was made of steel, just as an extreme case), the extra energy to drive the crack would be used in breaking the glue at the dowel-tenon interface. – aaron Jun 20 '18 at 12:06
  • You could actually use a steel dowel, make it shorter than the full width of the tenon, and then cover both ends with short timber plugs. Would look like a timber dowel from the outside but be stronger. – WhatEvil Jun 21 '18 at 9:37
  • Sorry, it was the increased glue surface area I was asking about. Increased from what? -_o – Graphus Jun 21 '18 at 12:17
  • @WhatEvil, stronger yes but why bother? Even more added strength is not needed. No way even a fairly modest hardwood dowel is going to fail in service on a static item with no dynamic loading. – Graphus Jun 21 '18 at 12:19

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