If the focuser on a Newtonian tilts / wobbles, suggested solution

On some Newtonians, the focuser is mounted to the tube via an adapter. This focuser is usually secured/clamped with small grub screws (M2). If the focuser doesn't have a groove/notch, a hole is drilled here, for example, into which the grub screw engages. If this hole is drilled too deep, the focuser will tilt over these two mounting screws and thus cannot be adjusted precisely. But it also won't rotate if necessary.

With an O-ring of the appropriate diameter made of Teflon or other rigid plastic, or as a temporary measure, with adhesive tape, the gap can be filled, preventing the focuser from tilting.

If we detect this during our inspections and before adjustment, we automatically correct the problem.