GRAFF center drill bit 4.0 mm for metal is a professional drill bit for drilling bores in various types of alloyed and unalloyed steels, cast iron, ceramic metal alloys. It’s manufactured from tool steel R6M5.
These drills are designed for high accuracy holes for further drilling with larger drill diameters. The drill bit construction ensures clear perpendicularity to the material surface due to a large difference in diameter of the working part and drill bit body. This peculiarity also provides a high fixity of a drill bit. No other drill type guarantees such accuracy and cleanliness of the bores.
Drill bits are used not only in professional operation; they can also be used at home – for drilling printed boards, in construction, as a countersink for metal or wood.
Parameters of GRAFF central drill bit: d = 4.0 mm – diameter of working part; D = 10.0 mm – diameter of drill body; L = 56.0 mm – drill length.