Roller skate axles come in two sizes, 7mm and 8mm.
So needing bearings for my daughter's skates, I pull a wheel
and Mic an axle.
Then I start looking for a conversion chart online.
For some reason I can't find one, I looked for over an hour,
pissed off I took a break and went to the thinking room.
Then it hit me.
I knew 5.5 6, 6.5, 7, 8, 9, 9.3, and 10mm.
I didn't need a chart, I already knew the answer!
Funny how I can go down a rabbit hole, and not see the obvious.
Multiply by 4.