Black Locust is an amazing wood. I have made several simple D-Bows out of it, and they shoot fast. They've held up well, too, despite some minor violations of the back ring due to poor ring-chasing efforts. Actually, BL is way harder to ring-chase than Mulberry or Osage. Go slowly, with short strokes to avoid pulling up splinters from the ring below. A flat cross-section is best, and it is a lively wood that seems to heat treat well. I Love the stuff. As far as identification, the bark is dark and gnarly, with deep furrows. There are great identification guides online. Honey Locust has smother, grayish bark, and the seed pods are easy to spot, like huge, brown string-beans. I don't believe the two trees are actually related. Black Locust is more closely related to Koa and the Accacias (I think). In my experience, the sapwood ring thickness depends more on how fast (i.e. how much water and fertilizer) the sapling is growing, than how big around it is. Trees about the size of a stovepipe are perfect, but a little tough to split.
