Lancaster Pump Upper Stretcher Pressure Block 12" Tripoli is an excellent compound

Tripoli is an excellent compound  for softer metals because on a microscopic level

but it can be done at 3600 RPM

Reaches into corners

The specially formulated plastic compound is the same one used by eye glass manufacturers to buff the edges of plastic eye glass lenses

Lancaster Pump Upper Stretcher Pressure Block 12" Tripoli is an excellent compoundUpper Stretcher Pressure Block These are the original and only units made in the USA by Lancaster Pump. Lancaster Pump holds the original patent for this metal Shrinker Stretcher concept. The Lancaster Pump Stretcher Shrinkers have been copied in China and their poor imitations are not near the quality of ones made in the USA. The Lancaster Jaws are a darker color indicating they are heat treated. The heat treatment process used on Lancaster jaws