For jewellery materials which are difficult to machine, such as pearl and corals, you need a drilling expert: these twist drills of finest grained hard metal have two cutting edges and two flutes, and have a substantially longer service life than traditional tool-steel or HSS twist drills on pealrs and corals.

Twist drill Fig. 4203 "HM"
Material: Finest grain carbide
Execution: 4 grooves
Range of app.: corals, pearls
Shank: 2,35 mm dia.
Rec. speed: 5.000 - 9.000 r.p.m. (freehand drilling)
Rec. speed: 8.000 - 14.000 r.p.m. (upright drilling)
Advantage: durable, solid construction