Vacuum Brazed Diamond Milling Bit used for milling groove of the inner side of stones. Vaccum Brazed Diamond Milling BitItemDiameterGritThreadGSBM2525mm50mmM14,5/8”-11GSBM5050mm50mmM14,5/8”-11GSBM7575mm50mmM14,5/8”-11GSBM100100mm50mmM14,5/8”-11 Vacuum Brazed Diamond Milling Bit