Collimation issues

[zidder]

I have got myself a laser collimator and made a focuser cap.

My issue is, when I use the laser to align the primary I get the dot in the middle of the target perfect, then I come to tighten the primary locking screws ( only finger tight ) and the laser moves out of alignment, this happens every time, the only way I can keep it set right is to leave the locking screws undone, this is bugging me big time. Is this usual ?

[Peter Drew]

Unfortunately, yes, this is usual. The best way to improve the situation is to very carefully tighten each locking srew a small and equal amount on a rotation sequence. 

[Jason D]

I have got myself a laser collimator and made a focuser cap.

My issue is, when I use the laser to align the primary I get the dot in the middle of the target perfect, then I come to tighten the primary locking screws ( only finger tight ) and the laser moves out of alignment, this happens every time, the only way I can keep it set right is to leave the locking screws undone, this is bugging me big time. Is this usual ?

This is typical. What you need to do is tighten the locking screws as if you are still collimating. That is, keep the laser collimator in the focuser and tighten a tiny bit each locking screws while keeping an eye on collimation.

Jason