FEATURE BULLET STYLE TEETH AND A FABRICATED BORING HEAD, AS WELL AS HEAVY-DUTY SINGLE FLIGHTING. 75 THICK BOTTOM FLIGHT AND A HARDFACE OUTER EDGE. The weld on collar is designed to break off if the bit gets jammed. We sell the replacement collars, teeth & tips. Jim Goodall Equipment Sales, 16327 Old US 41, Suite 301, Ft.