Originally Posted by
cudak888
One spacer, from a recent 7-speed or a disposed-of 6-speed UG cassette. Fits between the reversed threaded cog and the second smallest cog.
-Kurt
Thanks, I remember now - the outer screw-on cog is the only one with a lip on one side that acts like a spacer - the other cogs are flat on both sides and separated by actual spacers. So when you turn the screw-on cog around, its lip points out, so you need a spacer inside it.
When I tweaked a uniglide hub recently and flipped the outer cog, I got a spacer off an old worn cassette I had lying around.
I also managed to loosen the outer cog with just one chain whip, by keeping the wheel in the bike and bracing the pedal with my foot.