kennametal 62 straight bore insertThe 62 Series is a boron carbide straight bore insert with a 15. 9 mm (5 8") cylindrical OD, covering bore sizes from 1 8" to 5 16" for fine to medium precision spot blasting. Boron carbide delivers typically five to ten times longer service life than tungsten carbide with aggressive abrasives such as aluminium oxide and selected mineral abrasives. The 62 Series is made to be used in blast guns and equipment using the 5 8" insert format where