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SELECTING THE CORRECT CENTRE DRILL
TYPE "A"
For general centering operations on workpieces requiring additional
maching between centres.
TYPE "B"
(Protected Centre)
Sometimes called Bell Type
The 60° cone surface produced by this centre drill is recessed below
the surface of the workpiece and is therefore protected fromdamage.
TYPE "R"
(Radius)
The type "R" centre drill is also used for general centering operations,
but produces a radius centre suitable for a variety of male centre
angles eg. 60°, 82° or 120° can be used as an alternative to type "A"
above.
