Sintered Diamond Core Drills made with our exclusive metal bond developed for high strength and longevity，metal bond diamond core drills are the finest core drills manufactured in the world. Diamonds held in a metal matrix bond for core drilling glass, alumina quartz, ruby yag, silicon and other hard abrasive non-metallic ceramics.Sintered diamond drill bits are heavy-duty bits designed for long life.  Generally, sintered bits will have a long life of 20 to 30 or more times the life of a bonded diamond drill bit, if used properly.  The heavy-duty design provides long life when drilling in very hard materials such as porcelain tile, granite and hard stones.  However, there are some disadvantages.  Sintered bits are much more expensive than bonded diamond bits and the thick heavy-duty tip causes them to drill more slowly than thin-wall bonded diamond drill bits.