Valve Repair

We specialize in the repair and rebuilding of piston valves. All piston valve problems arise due to a discrepancy between the fit of the cylindrical valve piston to it's casing. In order to function properly and consistently, both the piston and the valve casing need to be perfectly round and free from any dents, bends, or excessive surface wear. Precision tools are used to repair the roundness of pistons and casings, lapping is used sparingly for final fit. In certain cases, when damage or wear is too severe to be repaired as stated above it is advisable to perform a valve rebuild.

Valve Rebuild

We perform valve rebuilds on all types and levels of brass instruments. It is cost effective to rebuild the valve on even a well-used student trumpet which has one or two pistons that have had significant damage, or have been overworked and are loose in the casing.

The rebuild consists of:
  1. Building up the piston diameter with copper and then nickel plating, and honing it perfectly round and to size.
  2. Honing the casing oversize. The honing is performed with state of the art Sunnen equipment which enlarges the hole incrementaly and rounds it out to a tolerance of 0.0001". Final finishing is done by adjustable laps, and the final fit of piston to casing is acheived by hand lapping.

After the valve refit, the action and air-tightness of the valve is restored to like new, and in some cases better than new condition.