I am in the process of starting a timber frame project. Historically, locust was often used for pegs. Unfortunately, I do not have any locally. I do have a significant amount of American hophornbeam. However, I can not find any information regarding shear strength. I have found articles regarding its use as tool handles and fence posts, suggesting good strength and decay resistance. Anyone have numbers to compare to other hardwoods?
(Sawing and Drying Forum)
From contributor T:
I haven't seen that info. What I have seen is much confusion among the experts on the common names. American hornbeam (Carpinus caroliniana) is aka blue beach, muscle wood and ironwood. Eastern hophornbeam (Ostrya virginiana) is aka ironwood. They are not often distinguished in technical documents and often erroneously interchanged. Maybe that's why technical info is hard to come by.
Settlers revered Eastern hophornbeam for its strength, durability and rot resistance. That's why it was used for wagon wheel hubs and axles. In other words, they used it where it counts. Most woodworkers don't like working with it because it is so hard, heavy and dulls tools quick. So it's now a forgotten wood.
My own experience with American hophornbeam suggests it is hard, heavy, and strong, but very prone to rot.
Just for kicks, you should check out a book about Japanese joinery. I have one that is way over my skill level, but still interesting reading.
I have a customer who brings me barn beams which I resaw for him into flooring material. I have found that tennons should bottom out into mortises, otherwise the pegs will sheer into three pieces. I have also found that about 50% of mortise and tennon joints have some sort of rot, if not completely rotted. I guess if there is any kind of roof leak, and water trickles down the beams, it collects in these joints, eventually causing the timber frames to collapse. Also, if the joint is loose, it is heaven for bugs.