I started chasing threads about 5 years or more ago. I have turned hundreds of boxes. I'm always looking for new to me woods that are dense enough to do it. I have a big old milk crate with what I call my box of learning mistakes. I save them so I can reuse them for reverse threaded chucks. The last few years, I noticed that some woods that were borderline are now ok for chasing, I had tossed them in the box after deeming them not worthy. Well, looks like it was me not worthy. Not enough experience. On some of the questionable woods I can now chase threads. Practice does give you perfection. Bill Jones said it takes at least 100 boxes to start to understand thread chasing and to get the hang of it. Since I do it the old traditional English bone grubber way, I do not use timber that some people would use CA. Moral of the story is, do not give up on chasing threads. it takes a bit of practice. Some people get it faster than others. In some woods is easier than in others. Working on Boxwood and Palo santo, just to name my 2 favorites, makes it easier, almost like cheating. African Blackwood makes you work for it, in part because is so dry. Compared to a big calabash, I hardly make any money on my boxes, but I love making them. To quote my hero, Bill Jones, "After 50 years, there still a sense of accomplishment whenever I end up with a nice fitting thread"