Clark's expansion bit, Fig. 401, is designed to cut holes of varying size by means of a shifting cutter. It is made in 2 sizes, one ranging from 1/2 in. to 1 1/2 in., and costing 7s. 6c?., and the other embracing all diameters between 7/8 in. and 3 in., and costing 11s. One of these tools not only replaces a complete set of the ordinary kind, but enables holes to be bored of all intermediate sizes. These, however, are seldom required in the general way.

Expansion Bit 402Expansion Bit 403Expansion Bit 404Expansion Bit 405