Some XLs have really stiff and hard to turn focusing cone situations that seem to defy all efforts to loosen thing up. Well - - - - I have found one thing that can cause serious stiff focusing on the XL. Here's how to fix it right away.

The actual focusing cone, the part with the knurl for gripping, is a tight fit to the bearing that bears the rotating load. It is such a tight fit that the three screws that lock the cone to the bearing are probably not necessary. These screws, on the outside of the cone have points that fit into dimples on the O.D. of the bearing as good design practice.

Problem:
If they are over tightened by a half turn the extra radial pressure lifts or bulges the cone in the screw area and expands it against the recessed I.D. of the body front plate. Yep, it's just like an internal expanding brake. If you look closely you can see the bulge adjacent to the screw. Sometimes the brake doesn't work until a lens is installed and this enhances the braking action by further warping the cone.

Fix:
Unscrew each screw one-half to one full turn. If this cures the problem, let me know about it. Email me or post a message.

Didn't fix it?
There is a tight felt light sealing gasket that rotates against this same recessed I.D. of the body front plate. this gasket is about 1/16" square and can induce some real braking friction if it is not properly installed or assembled. Complete disassembly is required to fix this problem. If it is the problem.