Saxon focuser shift?

[fuso]

Hi guys,
I have a 2nd hand 8' Dob which seems to have a loose focuser.:(

This is very frustration. cus when I put my laser in for collimation moving the focuser up and down the laser beam also moves about 2 cm.
The only way it seems to stop it is when I tighten the 4 screws near the R&P and also lock the screw at the top of the focuser (I don't know what that screw is for)
It reduces the shift/slop but the affect is a very stiff and hard to turn focuser.
Any tips on how to improve my focuser would be greatly appreciated.

Thanks Anthony

[asimov]

All you can do is adjust it correctly to take out the slop. There will be a very fine line between no slop + too tight & hard to move versus minimal slop & easy to move. Talking about thou's here.

Other than that, perhaps an upmarket focusser is in order.

[astro_nutt]

I owned a Saxon 8" dob and found that there are 2 allen head grub screws on the topside of the focuser barrel. You will need to loosen off the 4 screws under the R+P. Then very carefully tighten the allen bolt closest to the scope' tube until you feel resistence then back off 1/8th of a turn. Do the same for the other allen bolt. Go back to the first one and tighten until you feel resistence then back off less then 1/16th of a turn. Do the same for the other allen bolt. You can then tighten the 4 screws under the R+P, closest 2 first until you feel resistence then the back 2. If the focuser movement feels sticky then remove the R+P screws and remove the focuser barrel. Clean the barrel with metho and give it a good gloss with car wax. Reinstall the barrel and R+P.
Cheers!