Watchmaker's drill turn with whalebone bow.

These are two specimens of drilling machines sometimes used by watch and clockmakers and driven by small bows.

One has a forked frame with a lug at the bottom for holding it in the vice; one end of the fork is tapped to receive an adjustable back centre and the other has a plain hole through it. The spindle has a shouldered fore-end fitting the hole, while the back centre holds the shoulder up against the bearing. The nose of the spindle is bored for the reception of the drills, and it carries a pulley at its rear end for the bow string to act upon. The other specimen has a solid brass head with a plain bearing hole in which the spindle runs. The back end of the spindle carries the driving pulley, and the front end is formed as a split chuck for holding the drills. The spindle is held in position by a pin which engages with a groove in it. A bow for use with these turns is also shown, it is of whale bone and has a fine gut band.