Over time, the Heathkit SA series roller inductors fail. Sometimes the epoxy becomes brittle (or the original builder was too stingy with it), and sometimes the inner braid connection to the "solderable" shaft bolt (on the face plate side of the roller inductor) loosens and the wire snaps. When the shaft / bushing oil dries out - this can also cause these sort of failures - too much friction builds up - especially since there is the mechanical turns counter - adding resistance to the free spin of the inductor.
I tried to fix mine once, but it still worked loose, so I took a piece of very thick copper wire (approx. 1/8" thick), bent it in a U shape, stuck it through the two holes in the front of the roller inductor and then soldered it to the shaft bolt, where the electrical braid wire connects to the bolt. I also found that trying to use a lockwasher on the bakelite end cap is a bad idea - its best to use this soldered wire and then just tighten the bolt / shaft back the way it was originally designed.
The scariest part was taking a screw driver and mallet and using it to break the old epoxy seal on the front of the inductor. I was afraid that it might damage the inductor - but I was pleased with how strong and well built these old radio parts are - bakelite epoxied onto fiberglass.
If you do re-epoxy your roller inductor, it is very important to sand / scrape the old epoxy off - and be careful not to sand too much off the old bakelite. Also - make sure you lube the shafts of these old inductors and capacitors (where they pass through their bushings. I expect that some of the reason why my inductor worked loose and broke is because the shaft / bushing oil had dried. But use oil very sparingly - I used a "dry" bicycle chain oil.