Aiwa SDL60 cassette gear
 

I have an Aiwa SDL60 cassette deck on the bench. Having mucked out the decomposed belts and replaced them, I find that the fast wind drive gear has a radial crack. This component is nylon, with a 3mm centre hole which is an interference fit on a 3.5mm shaft. None of the replacement cogs on the usual sites are suitable (25 teeth, pitch diameter about 12.5mm), but I found a near-exact match from RS. This needed the centre boss cutting down, but is otherwise ideal, except that its centre hole is 4mm diameter. I've tried various fiddles with plastic shim, but none of these provide sufficient grip. I have tried a "welded" repair with a soldering iron on the original, but was not bold enough - the force required to re-fit the gear to the shaft split the crack open again.

Options, then - find a way of shimming the RS gear, which meshes beautifully, by the way; repair the existing gear with sufficient strength; find somebody to 3D print a replacement. This last was tried by an Italian contributor to YouTube and apparently worked, but my Italian peters out at "ciao!" - any ideas?

Re: Aiwa SDL60 cassette gear
 

Drill out the shaft hole in the RS gear. Spin up an adaptor in the lathe, glue. Have it turning in the lathe as glue curesbjust to keep it straight.

Advantage of drilling out is that the adaptor can be a sensible size.

If you want to show off, you can friction weld the adaptor into the bored-out RS gear.

David

Re: Aiwa SDL60 cassette gear
 

Can you superglue the crack in the original gear?

Re: Aiwa SDL60 cassette gear
 

I would certainly try to avoid friction-fitting the new gear on its shaft if you want to avoid a repeat performance.

ISTR that the recommendation for dealing with the cracked coupler on the Panasonic Z mech was to make things not-too-tight, then secure with Superglue.