kennametal 87 straight bore insertThe Kennametal 87 Series is a boron carbide insert with a straight bore. The insert is suitable for blast guns and other holders with a cylindrical 7 8" insert format. Several bore sizes are available, from 1 4" (#4) up to 1 2" (#8), for medium to heavier precision blasting and spot blasting. Boron carbide typically provides five to ten times longer service life than tungsten carbide when used with aggressive abrasives, such as aluminium oxide and