Whitworth drilling machine, of 1846

This drilling machine was made by J. Whitworth a Co and is fitted with the self-acting feed motion patented by Sir Joseph Whitworth in 1837.

The spindle is driven by bevel gearing in the usual manner; it has a screw thread cut on its upper part which gears with two worm wheels mounted on and keyed to transverse shafts. To the outer ends of the shafts friction rollers are fixed, fitted with brake blocks which are drawn together by a rod with right and left-hand screw threads. When the drill spindle revolves the worm wheels are rotated by the screw, but when the rollers are gripped by the brake blocks, the worm wheels are retarded and caused to act as a nut by means of which the spindle is advanced. A hand wheel on one of the transverse shafts is provided for rapidly withdrawing the drill, which it does by using the screw as a rack. The table is provided with T slots and can be both rotated and moved transversely.