From another thread on threads.
Wow. I knew I would find information concerning my current situation here on CN...
I have a 3Q74 Orange C8 SN 322744 (motors 6/74). I have had absolutely no issues hooking anything up to my base until yesterday. I've hooked up my optical back (original), a third party T48 to M42 camera back (purchased in 2021), an older Meade .63 reducer, a recent vintage 2" Celestron Diagonal from a 2" E-lux eyepiece and filter kit which all fit just fine.
Then I tried my brand spanking new Celestron #94175 Corrector/Reducer. I get about a third to a half a rotation before it stops.
OK, so maybe some "lapping" might be what I need for this particular device but I'm a bit concerned that there might be something else wrong with this corrector. At first, before I did a controlled experiment to determine how far I could get this on, I figured it was secure in my blind attachment. I attached my new 2" diag and eyepiece and the thing never made focus. I don't know if I have two problems here with the device and I should return it or "lap away."
Update:
So I borrowed a friend's Meade corrector. And my 2" optics do not focus with it, either. So the corrector seems to be fine on the other issue I thought I might have. Again, the Meade's threads are just fine, but it's an older corrector. Agena won't take my new Celestron reducer back without charges and any other new one would have the issue, so I might as well try one of the lapping exercises to "grind 'em down and make them fit."
But before I do.... Anyone else done this before? With only the telescope and the reducer to do the lapping? I'm sure, but my ability to do digital searches is sadly lacking. Thanks in advance!