Spiral drill bit for stone has width of raised edge of helical thread increasing along drill bit shaft in direction of drill bit head

摘要

The drill bit (1) has the shaft (5) between the fixing end (2) and the drill bit head (3) provided with at least one helical thread (7), with the width (x) of the raised edge (8) of the helical thread increasing in the direction of the drill bit head. The helix angle of the helical thread reduces along the shaft in the direction of the fixing end, with a simultaneous increase in the diameter of the drill bit.