TWIST BIT Russian patent published in 2003 - IPC

FIELD: tools for working of materials with various viscosity, particularly, in medicine for working bone tissues, in traumatology and orthopedics for performance of through and blind holes. SUBSTANCE: twist bit has rod and blades with backs and cutting part. Cutting part includes main and additional cutting edges, screw chip grooves and additional chip grooves. Chip grooves are made on rod and on rear walls of blades in one direction. Cutting wedges with depth of, for instance, 0.5-1.0 mm are made over entire length of one of main pair, cutting edges of blade. Side faces of cutting wedges are made with an angle not less than cutting angle of main cutting edge and cutting edge without cutting wedges is made for cutting chips in other plane. EFFECT: extended process potentialities in performance of operations on bone tissue without temperature rise in zone of cutting, and possibility of free transportation of chips of worked material from drilling zone. 2 dwg