Drill for hard materials, esp. concrete - has hard surface layer and is suitable for do-it-yourself applications

摘要

The drill is made of tool steel, esp. high speed steel, and the cutting head is coated with a hard layer at least in the region of the cutting edge. The cutting head may be provided with a conventional, brazed hard metal tip. The hard layer may extend along the flute(s) near the cutting head, and is pref. (a) hard metal carbide shot, grain size 0.01-0.3 mm., esp. 0.1-0.2 mm., applied by melting, esp. using an impact resistant brazing metal; (b) obtd. by hardening the tool steel by pulsed induction heating or an electron beam; (c) electroplated Ni contg. SiC.