Dear Barry, Perhaps you have some advice on getting the depth correct. The obvious solution is wires, for the outside thread (except for those who are lucky enough to have a thread micrometer.) How is the mating inside thread monitored for depth? This is the operation which was my worry when expressing concern. With a single start thread you can advance in small steps, using the outside thread as a gauge. With four starts that is a little trickier; you have to cut all four, test, and if more metal must be removed, repeat. Conversely, if one can measure, there is no big problem in advancing the tool the right amount. Unfortunately, I have never even seen a micrometer for inner threads!
You advice will be welcomed by all who might have to face this problem. Bob At 15:22 24.02.02 -0800, you wrote: >Hi Robert: > >Most multi start threads used in photographic >equipment use three or four starts. All I have made as >replacements have been 4 starts. This is easily >indexed using a machined block under each of the jaws >on the four jaw chuck. You can do it, only the first >one is difficult. The second time you do a multistart >thread it is cake. > >All the focusing helicals I have seen have 60 degree >included angle thread flanks. > >Barry Young _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
