I just removed camera + filter wheel + guider from telescope. Carrying that assembly to the workbench, it seems to rattle rather a lot, which I do not remember from when I first installed, just a month or two ago. Upon disassembly, I found the internal wheel that actually holds the filters, was quite loose and rocked back forth. I didn't measure, but I'd estimate 1/8" peak-to-peak, which seems to me is excessive, especially given that we want precise positioning of the filters. I have tightened up the central screw/bolt (I did not remove it, just tightened it): there is now only a tiny amount of rocking, and the unit no longer rattles when shaken, and the wheel still turns freely. But I am concerned that it has come loose in the very small amount of use it has had (two months old, maybe 4 or 5 sessions of taking images). What will stop it from becoming loose again? Does it need some Loctite? Also, what is the proper size/type of wrench/key for that central bolt? I am using one of the small hex keys that came with it, but the fit is a bit unsure. I don't want to damage the bolt. Also, the small toothed pulley that drives the belt seems to have a lot of "runout", i.e. non-concentricity. Some of it is a visual illusion, due to lines on the top of the pulley being non-concentric, but I think there is some real non-concentricity. I don't think it is loose on its shaft. Is this normal? Gary Billings
