Threading is one of the most automated programming tasks in modern machine shop, yet it could be one of the more difficult operations done on a CNC lathe. Initially, it may seem an easy procedure to make a program for a tool path that has the cutting parameters very clearly defined, such as threading. Practical applications, however, could present a big departure from theory. This comment may be arguable, at least until it is time to start searching for solutions to unusual threading problems or even regular threads that just don't seem to be coming out right. An experienced programmer should have the ability to think to yet another solution, when all the other solutions seem to have been used up. This is true for any problem solving process and applies equally to threading problems.

What often makes threading a difficult operation is the cutting tool application. The single point threading tool is unlike any cutting tool. Although the holder is mounted in the turret just like other tools, the cutting insert is unique. Threading tool not only cuts, it also forms the thread shape. Frequently, the threading insert has the shape of finished thread. The mounting of a threading tool in the turret can be at 90 to, or parallel with, the machine spindle centerline, regardless of thread being cut. The decision which way to mount the tool is determined by the angle of the thread, relative to the spindle center line. It is important...