The Black Diamond Valve Guide Honing System from Goodson Tools and Supplies is now manufactured using CNC technology to provide accuracy and consistency. It's available for guides from .193" to .389" (4.9mm to 9.9mm). The tooling is available by size or as a kit that includes four mandrel assemblies (.271" to 3.89" range), a drive head, four nylon bristle valve guide brushes, and an 8 oz. bottle of Diamond Honing Oil.
