I've been reading Science of Watch Repairing Simplified (1946), a self-published book by A. Gideon Thisell. It's an interesting book, with many neat ideas and turns of phrase. Thisell apparently was an instructor at one of Elgin's technical schools, and he has a lot to say. Anyhow, I thought of the recent thread on undercutters vs screw cutters when I got to the chapter on poise. When he describes ways of removing weight, Thisell writes: Filing the side of the screw head, or squaring off the pilot end of the thread are acts committed only by men that have no pride in their work. (p. 163) I've never seen a screw with the pilot end filed off. One can only imagine the dastardly desperado who would attempt such a thing.