... core drill bit,diamond core drill,soldered,after welding segments to core barrel,it is sintered in stove. ... core drill bit,diamond core drill,soldered,after welding segments to core barrel,it is sintered in stove. ... combined much more steady.It is not easy to lose teeth,last longer than normal brazed or ... welded core bit. Diameter from 27mm to 250mm is available.Segment height is 10mm. ¢27 ...