The Schwinn hub on my muni finally crapped out. It didn’t snap one side just
twisted about 10 deg and bend off center. Too much hopping down hills. Just
enough to be obnoxious. The timing was okay since I finished machining a new hub
and axle for the disc brake setup now in progress. I was surprised to find the
Schwinn hub axle reading only 15 on the Rockwell hardness scale when I measured
it this morning. That is very soft for steel shafting. Good industrial shafting
runs around 53 Rockwell. The axle I machined from 3/4" oil harding tool steel
came out of the furnace last night at Rockwell 57. That’s too brittle for an
axle, so it was soaked at 375 deg F for an hour to draw it down to 53 Rockwell.
Perfect. The hub and axle went for a ride today and seem okay. We’ll see what
happens after more rides are logged.
“The Muniac” firstname.lastname@example.org