I've had my SW Mak 127 for less than a month and used it a dozen times. I used a stock diagonal that came with it. When changing eyepieces I tightened 2 screws at the top of diagonal's barrell. So the knurled head screws were screwed in and out while tightening each new eyepiece.
Today I found that one of the screws stripped the inner thread in the diagonal barrell and the screw now falls off. I didn't expect it to happen (too soon?). What have I done wrong and how common is this failure?
I can tap a new thread in a different location or I may install a bushing in the stripped thread hole and re-tap the thread there but I don't know what should be my strategy to avoid this in the future? Should I not tighten the knurled screws when installing eyepieces in the diagonal barrell? What are they there for then?
Edited by JP-Astro, 17 May 2019 - 08:18 PM.