If the replacement nuts do solve the wobble problem, there should be no
more than the usual problems shared by all grinders. I've ordered new
wheel nuts from a local (to Boston) Ryobi service center, Panda
Electric. The people at this service center have clearly had things
apart, and understood the problem.
Well, the new arbor nuts arrived, and were duly installed. Made no
difference - the wheels still wobble badly. Time for diagnosis.
Using a 5/8" ID spring instead of the wheel, holding a flat washer
against the underside of the nut, measure wobble with a dial indicator.
On one right-hand nut, the wobble wasn't bad, so filed one face of the
nut perpendicular to the axis of rotation, to eliminate the wobble.
Tried the same on the left-hand nut. No dice. I would measure, file in
the counteracting direction, and on re-measurement the error would
increase or decrease, with no obvious pattern. Repeat. This went on
for at least an hour of growing frustration before inspiration struck -
measure the wobble as a function of how far the nut is screwed onto the
Bingo. Even plus or minus one thread makes all the difference in the
world, varying from no wobble to 0.020" wobble. The arbor thread is
drunken! Not visibly, but enough to make the grinder useless for any
non-crude purpose. No wonder it seemed random. Reassemble grinder, put
That grinder was good money after bad. Yet another unsolicited learning
I've written this grinder off, and am in the market for a real bench
PS. The left and right hand nuts came together in a bag, but so far as
I could tell no political arguments broke out.
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