I had to take the saw apart after all. I unscrewed everything that was attached to the arm and dismantled the hinge without dropping and cracking any cast iron parts. This is what I found:
1) There was a flat spot on the driving shaft to hold the set screw. This was too short so any movement of the wheel forward on the shaft would cause the set-screw to miss this flat spot and engage on the round part of the shaft.2) The set screw hole seemed to have been tapped twice - once at an angle for a part of the way and second time properly. Unfortunately the first channel directed the screw to itself preferentially. It took quite a bit of manipulation to line the set screw up properly with the correct channel.
3) The lip of the first channel cracked at the mouth and could no longer support the set screw - thus my arrangement with a plug etc. had no chance of working for at least two reasons.4) Having cleaned everything up I extended the flat spot on the shaft and repositioned the wheel and the set screw. After reassembling the whole thing it seems to be cutting satisfactorily. However, under load the driven wheel has a discernible wobble. It does not affect the tracking of the blade at the current settings. I only saw this after I put everything back together so I do not know if it is the shaft or the wheel itself.
5) All of the screws I had to deal with were imperial but *the heads were metric*, i.e. 1/4" screw would not turn with a 7/16" wrench, 10 mm was needed, 5/16" were slipping with 1/2" wrench and needed 12 mm etc. (3/8" were of course OK with either 14 mm or 9/16" :-)6) I found the Busy Bee manual for this machine - note the parts list:
Now back to some productive work...
Michael Koblic, Campbell River, BC