In the current issue of WOOD magazine, they give plans for a nightstand.
The side and back aprons are 8.75" deep with 8.25" tenons. The tenons are
cross-grain glued into the legs!
Has someone repealed the laws of wood movement?
I think I'll write them and ask :-).
On Sat, 04 Oct 2008 09:11:27 -0400, Phisherman wrote:
I know that, but apparently they don't. In addition they left no slop in
the mortise to allow for such expansion.
If the aprons were glued only at the top, there wouldn't be sufficient
support for the legs. What I would do is separate the single large tenon
into three smaller ones (2"-3"-2") with space between them and at the ends
of the mortise. Then I'd glue only the top and bottom 2" tenons and let
the middle 3" one float.
I'm referring to the Nov/Dec issue as it's only published every other
Not seen what they're actually doing, either, but seems like that would
still be an issue as the middle one isn't the one that needs to move.
Seems like two fixed tenons on either side of a 8" wide piece even
individually narrow are still likely to need some way to move relative
to each other or will eventually fail the joint.
I don't recall a mention of the parts thickness, but a time honored general
'rule of thumb' is that a tenon should be no wider than 5 times it's
thickness before going to another tenon.
This is pretty standard stuff in door making, which makes liberal use of
double tenons on some pretty wide rails, with either a space or haunch in
the middle, each component being no more than 1/3rd the width of the rail.
Depending upon thickness, on a wide table apron I'd probably forego a haunch
in the middle, but use a "haunched mortise and tenon" for the top tenon of
double tenons, so it doesn't break through the leg endgrain.
Following either above, it is accepted practice to glue both the top and
bottom tenons. I've never had trouble doing that, but nothing I've built has
been around longer than 45 years either.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.