Harold and Susan Vordos wrote:
Not if the gears are heat treated. THe HCl treatment would have introduced
hydrogen to the gears, making them subject to breakage (hydrogen
embrittlement). They should receive a roast for a couple hours @ 375
degrees F to eliminate the hydrogen.

Good to know! So far I've only derusted the one in the picture. I'll
check them and use another process if they're heat treated. I assume
that hardness is the indicator of heat treating.

Thanks,
Bob