Posted by Chuck Awot on January 01, 2001 at 22:34:34:
In Reply to: manufacturing worms posted by Bob Mullin on November 18, 2000 at 21:08:32:
There are a number of means of fabricating worms, depending upon the accuracy and volume that you need to attain. For high volume types of applications, people will very often roll the threads on the worm. This will generally provide a fairly accurate worm with a good surface finish, but it costs an arm and a leg to tool up for it. Finish thread milling can be done, but you may have problems with thread to thread spacing, depending upon the accuracy of the equipment that you have available. Finish hobbing will also provide a reasonable finish, but the thread to thread accuracy obtained is generally better because of the generating process. If a very high accuracy, or very good surface finish is required, worms are usually finish ground after heat treat. Most people normally use a good carburizing steel for worms to be heat treated. There are a number of ways to finish the ends of the threads. Most of the newer CNC thread milling machines and grinders have the capability to relieve the thread ends by using the center of the cutter on a thread mill, or the center of the grinding wheel on a single rib thread grinder wheel. I,ve been making worms for over 20 years, so if you have any more specific questions, let me know, and I will see what I could do to help you.