valve grinding automotivevalve grinding centerless
VR12 Valve Refacing Machine with Centerless . Rottler''s Centerless Grinding System rotates the valve stem on it''s own centerline. Precision drive rollers rotate the valve stem and a pneumatic low friction steady rest support the valve stem similar to a precision balancing machine, resulting in extremely accurate valve stem to valve seat run out less than .0002 (.005mm) TIR.