Dormer a777 heavy duty cobalt jobber drill for use when greater heat is generated during drilling eg on higher tensile tougher materials and in particular the aerospace industry specifications flute geometry standard helix right hand spiral thick web point angle 030 mm 095 mm 118 conical point100 mm to 140 mm inclusive 135 4 facet point150 mm and above 135 split point sizes split point geometry to nas 907 areospace specification type p3 point surface treatment bronze material hsco cobalt st