For simplicity, I'll refer only to the mortise in the post, alhough the same would be true in the beam. Yes, the thrust from the brace is directed along the brace, at 45 degrees. Thus, there are 2 surfaces that bear the load. The bottom of the mortise is one of these critical bearing surfaces, the other is where the shoulder of the tennon contacts the post. You would be correct about the back of the mortise if there were no shoulder. CB.
Originally posted by Jerod:
Thank you for your comments. A question about the brace mortice: I have been looking through a book by Jack Sobon in which he cuts the brace mortice to 90 degrees at both ends (no 45 degree to match incoming brace). Intuitively I imagine a brace in compression wanting to thrust inward with only a corner and pegs to stop it. But even with a 45 the movement of the wood or poor workmanship may also leave a gap, hence the same situation. I am wondering if it is common to cut a 45 or 90 on a brace mortice and what areas of contact are critical? Also on 8" deep braces would two 3/4" or 7/8" pegs be preferrable to one 1" peg. Ken Hume, I refer to your comment about smaller pegs resisting relish failure marginally better and two pegged braces. Thanks
