One more question regarding scarf joints...
When designing the joint, are there rules of thumb for the dimensions? Such as length of bridled tenons, peg placement and size, tenon width, angles for undersquinting, etc?
The tenon on a bridled scarf should be long enough so that the relish doesn't blow out the end of the tenon. So you could use the 4 diameter rule. That is the hole location should be 4 diameters from the end of the tenon. Or consult the latest peg locations document put out by the timber framer engineering council on peg locations.
As for peg size. One standard is that the peg size is 1/2 the size of the tenon width. So for a two thick tenon a 1" peg should be used.
I don't recall any angle standards for undersquinting. But again as mentioned in another thread about scarfs you should make the overlap between to pieces four times the depth of the timber. 10" deep then 40" long scarf.
Jim Rogers
