Review on 🔨 Optimized American Convex Thickness Pattern Breaker by Steve Quinn

The conical shape is good, but the inclination of the teeth causes the file to move to the left, creating asymmetrical grooves. To make matters worse, it facilitates threading in one direction and hinders threading in the other. This is not a major problem with flat files, but it is very noticeable with half-round files. Basically, it only works when you're driving with your left hand, but it snags and breaks when you're driving with your right.