Detailed Product Description supply core drill bits steel back, for diamond tools,OD 23.6-80mm, length 82/135mm, with 2 or 3 grooved, etc,material: steel 45#, or othersCertificate: ISO9001:2000or processing according to supplied drawings or samples.We have CNC lathe, milling machine, auto lathe, drilling machines, saw machine, and so on.Weclome the inquiries from all over the world.Fuzhou ...