Fixing run-out on a metal spindle

2015-04-17 18.01.16 2015-04-29 21.48.10

I am in the process of restoring a turn-of-the-century hand crank bench grinder that I found at Charlie’s Second Hand Tools. It was relatively functional when I found it, but the spindle was wobbling slightly.

After using the tool for a while, I began to realize that the wobble was an issue and decided to attempt to fix it. There are several approaches to this issue that I’m exploring, both conventional and unconventional. Traditionally, this has been corrected on a lathe with a dial indicator. I don’t have a dial indicator or a lathe. To hire a machinist to repair the spindle would be prohibitively expensive as well. I didn’t pay more than $40 for the tool and they’re worth < $100 restored. I would hate for this retro gem to be “totaled” so I began exploring other options.

Essentially a dial indicator is simply a rotary ruler. They cost between $15 and $100. I could purchase one of these, but then there’s still the matter of mounting it in such a way as to give a reliable reading.

At this point, my best idea is to mount it in the original device and apply heat to correct the bend. If the indicator is reading above baseline, apply heat to the measured side; if it’s measuring below baseline, apply heat to the opposite side. The heat will expand the steel unequally, correcting the run-out.

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