Loose tenons

[Ted Friesen]

I'm planning to building an entry door for my shop. The styles and rails will be 8 quarter by 4" vertical grain Douglas fir. The bottom rail will be 8" wide. What size of loose tenons or multiple tenons should I use?

I was thinking of using double ½" thick tenons 3" wide, spaced ½" apart. That follows the rule of thumb I have seen that the tenon should never be more than 6 times its thickness.

Does anyone have advice about wood species to use for the loose tenons? I could use up some hardwood scraps or use the fir cut-offs.

Any advice would be appreciated. This is my first project of this kind.

Ted

[Chris Friesen]

You've probably already seen it, but: http://www.popularwoodworking.com/te...ules-on-tenons

The above is written for integral tenons, so just factor in the additional length for the loose tenon. Personally in your situation I'd probably go with 3/4" thick tenons, assuming you're aiming for 1 1/2" final thickness. For the bottom rail either do double tenons like you suggest (with one of them not glued fully to allow for expansion) or else a single 4"-wide tenon with a haunch running the full width of the rail (with the haunch not glued fully).

For the species, I'd go with the same species as your project wood, that way it will move with humidity the same as the rail, making that glueline less likely to crack.