Hi everybody,
This seems like a basic question but I don’t recall ever seeing it addressed. Consider a table apron that is mortice and tenoned to the table leg. The grain in the leg runs vertically, while the grain in the apron runs horizontally. How wide can the apron be before you run into problems over time with wood movement since the grain in this join runs in opposite directions?
Thanks!
Replies
You cant have an apron that is much wider than 3 inches without interfering with your seating at the table, at this width there has never been a problem. I have built doors with 7 inches wide tenons that have not caused problems either, I would not bother.
If your piece requires an unusually wide tenon you can deal with it the same way we deal with long breadboard tongues.
The point isn't the apron (that was just an example to explain what I'm asking about).
Thanks for the suggestion about breadboard ends... That doesn't quite get at the answer i'm looking for either. I'm asking about the width limits of a single glued tenon. I'm not thinking of a specific application at the moment. I just want to understand the limits.
If you pin the tenon at the center and leave room for expansion and contraction such as in the breadboard design. there is no limit to how wide you can make a tenon. If you simply glue a regular tenon I would not go beyond 6 to 8 inches wide and favor quartersawn wood which would cut in half the wood movement in the direction of the tenon width.
Thanks! I appreciate it, that’s what I was looking for!
Agree with what Gulfstar said.
Keep in mind movement depends not just width the cut and to some extent species, for example quartersawn < flat sawn.
That said, I pin just about every mortise I do in a table.
Here is an example of my mans cave doors built in 2014 out of 6/4 white oak. The lower cross piece is 9 inches wide, the top 5 inches, they have not moved . Glued with marine epoxy thickened to syrup consistency.
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