Test watch balance wheels that the rims are concentric with the staff axis.
What does a Balance Truer do?
Tests and adjusts watch balance wheels to ensure that rim is concentric with staff axis: Mounts balance wheel and staff on test stand or between jaws of truing II calipers, using tweezers, and twirls wheel by hand. Determines that dial gauge readings are within acceptable limits as rim of revolving wheel brushes against gauge arm on test stand, or determines no clearance variation between rim of wheel and caliper index pointer placed above rim, using loupe. Bends rim to eliminate distortions, using tweezers or rim wrench.