Needed a 60 degree center and this seemed like a good choice based on reviews. For the first few months it was just a good choice. It worked well, especially with my pin mandrels, but after about 7 months I noticed that it wouldn't catch when inserted into the work piece, and then I noticed that the mandrel slips out, and even when I screwed it back in . into a cone, it comes right back out. In the end I used a drop of Loctite to fix the threaded ring. It still works fine with the "repair" but I'd rather it work as intended without my help.