... chipping, 3 minimum material deformation 4 long life Diamond glass core drill bits are used to drill glass,ceramics, porcelain, ceramic ... -resistance,high efficiency, long service life.Diameter: 5mm - 100mm.General Total length: 55mm, 65mm, 70mm,75mm,90mm,95mmService life: can dig ... points All products above can be customized. thin wall diamond core drill bit with threaded shankfor glass