... 160mm 2.Style:round triangle,hexagon shank;In &external thread 3.For glass,ceramic,marble etc. Jiangyin JingLing Diamond Abrasive Tools ... 1)Round shank, triangle shank & hexagon shank available; 2)In thread & external thread; 3)Key drill & no key drill. 3. Suitable for ... drilling holes on various hard Non-ferrous materials, such as glass,marble,ceramic,granite, hard materials etc. 4. Smooth drilling ...