Quote:
Originally Posted by marki
Dont' mean to hijack the thread here. Bill, most the threads on CCD camera's are 0.75mm in pitch regardless of diameter and are absolute sods to cut on a lathe as it is difficult to get proper depth (~ 1.25mm) using a standard 60 degree thread cutting tool whilst retaining the correct thread form. I have cut a few but have never been really satisfied with the result as they are either too tight a fit and bind due to lack of depth or too loose through overcutting the thread to reduce friction. When I get time I intend to grind a purpose built set to carve internal and external threads to the right profile but these will be very delicate as the cutting tip and shoulder will only be 0.75 mm max width. What is worse is that only 6061T6 ali or the british equililant HE30 seem to be able to cope with the cutting pressure with all other grades and tempers of ali I have tried simply tearing away as the thread is formed. I believe the threads on most comercial bits and pieces are roll formed giving the unique pitch and depth characteristics present. I have found there seems to be little consistency between manufacturers from different countries for example my german made astronomiks filters bind in both the QHY and FLI filterwheels and the american built bits seem to bind with anything other than US made components and even this has shown to be a bit hit and miss. Steve at my astroshop or Mogg adaptors might be able to help. There is also another mob whose name I cannot remember but folks around here have mentioned them before.
Mark
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Have you tried these:
http://www.machineryhouse.com.au/L031
I've cut quite a few 0.7 and 0.75mm threads in 6061T6 with them and they seem to work fine if you take it slowly.