scope:

Scope and field of application

This standard applies to unthreaded 60° centre holes for general engineering purposes. Centre holes of type R, type A up to and including size 12,5 mm X 26,5 mm, and type B up to and including 10 mm X 21,2 mm are made with type R, A or B centre drills as specified in DIN 333. Type A centre holes above size 12.5 mm X 26,5 mm, type B centre holes above size 1 O mm X 21,2 mm and type C centre holes are normally manufactured by means of two or more tools in different, successive operations. For the centring portion of type C centre holes up to and including size 12,5 mm X 26,5 mm or 10 mm X 2 1,2 mm, however, type A or type B centre drills as specified in DIN 333 may be used, since the centring portion is the same for types A, B and C.

Unspecified details of the centre holes made with centre drills result from the shape of the centre drill (see Explanatory notes).

See DIN 332 Part 7 for the determination of d₁ for a workpiece mass up to 28 O00 kg.