Try automobile brake cleaner fluid on both bearings to loosen it. Then flush that out with WD-40. Finally use a toothpick to put just a very little white lithium grease on both bearings.
If treating the bearings chemically doesn't loosen the shaft, it would seem that it is mechanically stuck somewhere.
72 es GL,
Date: Tue, 14 May 2013 09:18:01 -0500
Subject: [4sqrp] Stuck capacitor
I have a "perfectly" good dual gang 400 pf variable capacitor from an
old Heathkit signal generator. The only part of it that is NOT perfect
is the fact that it is extremely difficult to turn. I cannot grab the
shaft and turn it by hand. It will turn if the shaft is clamped in a
vise. I'm hoping to attach a stepper motor to it and would like it to
turn a lot easier. I've tried oil, WD-40, solvent, and white bicycle
lube on both end bearings, but that didn't seem to help at all. The
center bearing, if there is one, is covered and not accessible.
Any suggestions before I break down and get a new one?