GR-3770 Kpmi, valve guide reamers 0.3770 hss

This Kibblewhite valve guide reamer is precision-ground from high-speed steel to a diameter of .3770" (9.5758mm). It is designed for the accurate finishing of 5/16" valve guides across various materials, including cast iron and high-strength bronze alloys like C630 and Ampco-45. Proper guide sizing is critical for valve stability and oil control in V-twin engines. This professional-grade tool allows engine builders to achieve the exact clearances required for high-performance or stock applications. The durable HSS material ensures that the tool remains sharp and accurate, providing a consistent finish that is essential for cylinder head work.