kennametal 60 straight bore insertThe Kennametal 60 is a boron carbide insert with a straight bore. The insert is suitable for blast guns and other compatible holders with a cylindrical 9 16" insert format. The insert has an outside diameter of 14. 3 mm (9 16"). One bore size is available: 1 4" (#4 6. 4 mm), with an overall length of 38. 1 mm (1 1 2"). Boron carbide typically provides five to ten times longer service life than tungsten carbide when used with aggressive abrasives, such