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Old 26-01-2011, 08:30 PM
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erick (Eric)

erick is offline
Join Date: Dec 2006
Location: Gerringong
Posts: 8,490
My old Celestron C8 should have a 2" 24tpi thread. I have a GSO diagonal that fits, but two other GSO accessories (a straight-through 2" and a 2" Crayford focusser) that do not fit. All my reading suggests they are all nominally 2" 24tpi, but that thread tolerances were changed at some stage enough to cause this problem. My micrometer and thread gauge work suggests it is a thread depth problem. I am waiting to sit down with a machinist to work through all the threads, accuately measure them and see what we can adjust.
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