Question

__________________ is used in a power or hand drill to form the conical recess for the heads of countersunk screws.

(a) Countersink bit

(b) Carbide insert bit

(c) Hole saw bit

(d) Flat wood bit

This question was posed to me in a national level competition.

I need to ask this question from Equipments topic in chapter Construction Equipments of Construction & Building Materials

Answer 1

The correct choice is (a) Countersink bit

To explain I would say: Countersink bits tends to be designed for use on soft materials such as Timber and plastics, not metals. When used with a power drill to countersink an existing hole, the bits tends to chatter, leaving a rough surface. Better results will be obtained in the counter sink bit is used before the hole is drilled.