If the focuser is too easy or too stiff...

Product Description
If the focuser is too easy or stiff to move, it can almost always be adjusted using a set screw in the center at the bottom.

The tighter the screw, the stiffer the focuser becomes. Too tight is bad. The set screw presses on the shaft of the Crayford focuser or on the gear on a rack-and-pinion focuser (RPA OAZ).