Widia produced a tungsten carbide, derived from "like diamond - Wie Diamant (Ger)". The first Widia tools were available on the open market in 1923. They consisted at that time of approx. 94 % tungsten carbide and 6 % cobalt. Today's types contain additives that improve the hardness etc.
The Widia disc cutter is ideal for cutting clean-edged openings in GRP fuselages. The shank fits any mini-electric drill.
For cutting window openings you should prepare the corners with the hole cutter beforehand, otherwise there is a danger of over-shooting the lines. The shank fits any mini-electric drill with collet chuck of 3.3 mm.
Wear protective goggles!