Balancing flywheels, now that can be a challenge. I have heard about balancing flywheels for years, but I never saw how anyone does it. (There must be electronic devices for this used by the big companys.) I decided to build my own balancer. I found some very small precision ball bearings with close to 1/8" I.D. (actually a hair less, metric?) and I used these. It actually works, I have balanced a few flywheels, but it is a tedious process where something like a crystal ball would also help. More than once it looked like "remove a little bit more about right here and that should do it", but it does something different than expected. Experience and learning when to leave well enough alone helps with this process. Sound familiar Scott? or do you have a majic wand for this?