How does a lathe make a round wooden spindle?

A lathe makes many rounded parts by turning the material while a cutting tool removes thin shavings. A wooden chair spindle can begin as a thicker piece of wood. As it spins around a fixed line, the tool trims away material outside the wanted shape.

The machine holds the workpiece securely and rotates it around its axis. A supported cutting edge meets the moving surface. At one position along the length, the tool removes high points as each part of the wood comes around. Continuing the cut makes that section round about the same axis. Moving the tool along the piece makes a longer cylinder.

Changing how far the cutting edge reaches toward the axis changes the radius of the finished surface. A deeper cut leaves a narrower section. A shallower cut leaves a wider one. A carefully changing tool path can therefore make curves, grooves and shoulders along a spindle. The resulting surface repeats around the turning axis.

The removed material becomes chips or shavings. It is not squeezed into the finished part. This differs from pressing soft material into a mold. The starting piece must contain enough material everywhere the final shape needs it, and a tool cannot restore wood already removed.

Lathes also shape metal parts with suitable tools and machine settings. Their common idea is relative motion: the work turns past a cutting edge. A smoothly rounded object can reveal a repeated action in which every point around its surface passed the same tool.