Lathe-shears. The frame of a lathe that carries the head and tail stocks, and that rests on legs.

Lead-screw. A screw for a lathe that is used for screw cutting only.

Left-hand thread. A screw thread in which the nut must be revolved in a direction opposite to that in which the hands of a watch move, in order that the nut may screw upon the bolt.

Leg-vise. A machinist’s or blacksmith’s vise having legs.

Line of centres. A line, real or imaginary, passing from one centre to another.

Line out. To mark on work lines denoting the depth of surface that is to be cut away.

Liner. A piece of iron put behind or upon a piece to take up its wear.

Line-shaft. A shaft employed to transmit motion from an engine or motor to distant points.

Link. A piece having holes or pins at its end to connect two other pieces together.

Live centre. The centre of the live spindle of a lathe.