[Chas]

Just to inform: Using a large knob with an Allen set screw to lock it on is fine, but tightening the set screw tight would ordinarily cause an indent in the flat of the shaft, like from a cone point or a cup point set screw. A flat or dog pointed setscrew will still get a good grip but wont chew the flat of the shaft. If there is no flat this is more important as it may be a problem to get this large grip knob off if a cone or cup pointed set screw has mushroomed the shaft, fix one problem and create another?
Though the steel shaft will expand with the heat the bushing will expand more, the added space and heat will cause the "shellac" harden lubricant to mix with any oil added and give way.

Its great to get things moving again but to damage them in the process, well, not workman like.

GL

Chas