Est. 1998 — 27 years of woodworking knowledge
Stub or through?
Patrick Gibbons
>Pragmatically is there any difference between using a stub tenon or a through tenon in a given application? The application in question is the assembly of head and foot boards for bunk beds. I will drawbore the joints. I imagine a through tenon provides more glue space, which is a positive thing. The legs are 2 1/2" wide. If I use a stub it will be approximately 1 1/2" long. The design would not be inhanced or diminished by the use of either.
Re: Stub or through?
joel
>stub tenons are easier as they can't be seen and you can be sloppier.
Re: Stub or through?
David Linnabary
>Through tenons can be wedged which would add significant structural strength to an application that typically gets a greater than normal amount of racking stress. Try to imagine your m&t standing up to a 50lb kid romping around at the top of a 5-6 foot long bed post.
Any looseness in the framework that occurs over time would be amplified in a structure that is twice as tall, as in the case of bunk beds.
David
Re: Stub or through?
Scott in Douglassville, PA
>The bed I'm fixin' to build will have the front and rear rails wedged through-tenoned. I chisel the mortise out a few degrees, wedge it, and I've got an internal dovetail-type thingy. Strong stuff, Maynard...
Re: Stub or through?
Todd Stock
>1.5 inches is plenty of tenon, assuming that the upper and lower rail tenons are of decent width. If you are really concerned about strength, add another 1/2" or so, but you probably already have 20-30 square inches of gluing surface on each post.
Where you might consider adding beef is at the side rail/headboard joint, which these days seems to get a pressed sheet metal connector or a dowel or two and a 1/4-20 connector.
You might look at going with stub tenon on the rail (3/4" wide by 3/4" long or so) and bed bolts through the posts. Tighten the bed bolts every year or so, and hand the wrench down to your great grand kids when the time comes - the bed will still be in use.
My experience has been that the sheet metal connectors either strip their end-grain fasteners out of the rails or fail in shear.
tenon strength vs length data
Bill Tindall, E. TN
>data taken from Franklin applications publication
the strength is a torsional strength(bending)
tennon length strength
0.5" .48
1.0 1.00
1.5 1.28
2.0 1.66
Country boy sez
jim_reed@marietta
>My unscientific testing of cabinet door frames shows that thru tenon is much stronger. If you do thru tenons, be sure to mortise from both ends and meet in the middle.
Re: Stub or through?
Jim in Burlington Ontario
>Should they ever need to be moved bed bolts. You could use stubbed tennons which are easy and fake thru wedged tennons for the look.