Page:Turninglathes.djvu/18

Rh The second Lathe head, or back poppet as it is usually called, is movable along the bed, and can be fixed at any point by the bolt and nut attached to it. The upper part is bored out accurately to carry the cylinder, or smooth, round bar into which the pointed steel centres fit, which are used to support work while it is being turned. This cylinder is advanced and withdrawn by a hand wheel at the back, which carries a screw working into a nut in the cylinder. All this is out of sight in the upper part of the poppet. Between the poppets stands the hand rest, on which the tool is supported. This can be placed where needed, and the upper part, or tee, can be raised or lowered at pleasure, according to the size of the work that it is proposed to turn. This hand rest is often replaced by the slide rest, if metal is to be turned; but a good deal can be done without this addition to the Lathe, which can be added at any time, after wood turning has been thoroughly mastered.

In the illustration (Plate I.), all the parts above described are lettered as follows:—

A, A, Standards.

B, Bed or gantry.

C, Treadle.

D, Crank hook, pitman, or chain gearing.

E, Crank axle.

F, Flywheel.

G, Lathe cord.

H, Fast headstock.

I, Movable headstock or back poppet.

J, Hand rest; and K, its T or tee.

L, Hand wheel to move M, the cylinder.

N, Mandrel, with its pulley, O.

P, Screw for chucks.

Q, Tail pin.

R, R, Treadle centres or bearings.

S, Movable back centre.

T, Bearings or centres of crank axle.

We now come to what are known as chucks. These are contrivances by which the work to be turned is secured to the Lathe mandrel, and they vary according to the size and