My first attempts of making Black Locust bows failed miserably.I was using wood with very thin growth rings. I decided to remove the bark like a white wood bow, and use late growth ring right under the bark for the back. Results were 2 broken back bows. I then found a dead log that was hollow in the middle with some very nice consistent growth rings. I chased a nice thick ring for the backs, and got 4 really nice bows from that log.9 growth rings per inch measured at the handle. Thicker, and more consistent than Gregory's, but not as thick as Bob Barnes example.