The cones on my Top Flite balancer touch each other before they hold the prop tight. Can they be trimmed so they don't touch in the middle

Not really, there's an O-Ring on each end of the cone

When the prop is to thin for the cones and they touch, reverse one cone on the rod with the flat side aginst the prop face and the other cone will go in far enough to handle the centering.

John

Thank you John. I knew there was a way to do it, but my brain just wouldn't engage! [&:]

We all have a sticky gear engagement from time to time