Suitable for hard and soft wood veneered wood laminated chipboard plastics ideal for laying pipes airing and ventilation pipes switch and junction boxes professional quality with hardened teeth teeth and cutter hardness are finely balanced to the application note recommended speeds at 25 mm diameter 1500 rpm at diameter 50 mm 800 rpm at diameter 100 mm 200 rpm 6 piece hole cutter set hardened medium cut teeth with the appropriate cooling also suitable for cutting non ferrous