The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: SwampDonkey on November 24, 2011, 04:46:30 AM

Title: Mortise/tenon question
Post by: SwampDonkey on November 24, 2011, 04:46:30 AM
I am working with 2" material and I want to use pegs and pins in the construction of a small frame. It wouldn't have much weight on it. Maybe 20 lbs per joint. But I was wondering a if 1/2" tenon was meaty enough? It will be set into a 3" deep mortise. I wanted the mortise side walls to be 3/4". I will pin the far corners of the frame with two pins with a 45 arrangement through the mortise side wall. I'm making it this way along with pegging cross members so as to be able to knock it down for moving. I'm not using any glue. All it has to do is resist rocking. There will be a number of members on each side of the frame that cross at 90 ° to help with that I believe.

So any concerns with 3" long by 1/2" thick tenon wood?   ;D
Title: Re: Mortise/tenon question
Post by: WDH on November 24, 2011, 07:03:40 AM
No issues from what I can see.  Without a lot of weight or racking pressure, that should do just fine. 
Title: Re: Mortise/tenon question
Post by: SwampDonkey on November 24, 2011, 07:35:18 AM
Yeah, the racking from side to side will have beafier pegged tenons and a couple large slip on dove tailed joints for this purpose. Probably 1-1/2" thick on the tenons.  8)
Title: Re: Mortise/tenon question
Post by: Texas Ranger on November 24, 2011, 08:44:40 AM
Swamper, all my local wood working friends tell me I over engineer stuff, so, the bigger the better.  No weight, fine, any constant taking down, setting up, moving, could eventually split out the mortise.  And why a 3" mortise? If it is not a glue up, this could weaken that member.  Besides, 3" takes longer.

Just thoughts after my door making career.
Title: Re: Mortise/tenon question
Post by: Raphael on November 24, 2011, 10:44:49 AM
The rule(s) of thumb are make the tenon 1/4 the thickness of the morticed material for large stock and 1/3 for small stock.  I'd say 1/2 inch is adequate.
Title: Re: Mortise/tenon question
Post by: SwampDonkey on November 24, 2011, 10:46:59 AM
It won't be moved often Tex, like years. I'll likely be in the grave by the time it's moved the 3rd time. I know, selfish. Too bad. :D There are only 4 corners being done this way, the other joints are 2" deep. 3" on the 4 corners so I can put 2 small pins in. They only have to secure it, not bear a lot of weight. Probably the first one to break will be from dropping the timber and busting a tenon on concrete. :D

Thanks Raphael. :)