Grinder Arbors
With some smaller grinders, I have had problems with wheels that did not fit: 'English / inch' measurements did not line up exactly with 'metric-almost-equivalents'. In other words, 7/8" did not equal 7/8".
Measured the arbor O.D. on a number of
what-should-be-identical, 511A type grinders.
Surprise!
1) Arbors not all the same (see measurements* below).
2) Most arbors were not perfectly round!
* I am not a machinist, and only had a a HF digital caliper, but I made several measurements of each, so they should be close, if not exact.
Oregon 511A
_______ 0.868 - 0.8695"
Speed Sharp Star
____0.8695- 0.870"
Tecomec Super Jolly
_ 0.8715 - 0.872"
Oregon 520-120
____ 0.871 0.8735"
This is not an issue if you are not having problems with your grinder and wheels. I was trying to have a bushing made to let me mount wheels with larger I.D. holes. Six thouandths variation seems like a lot to me; might be a little less if I knock down a few high spots with some emery cloth and a stick.?
Philbert