Cutting screw threads on the lathe
Planes and guides for the male and female threads, and a drawing instrument
The sheet lays out a method for cutting screw threads on a lathe: a threaded spindle stands in a tall frame at the centre, flanked by a round plane and blades for shaping the male thread and by a guide for forming the matching female thread. Leonardo notes that the plane's iron is set three or four times deeper in one pass than in another. A long bench-like instrument for drawing runs across the foot of the page, its two clamp details marked female and male.
On this page
Method for making screws on the lathe
A heading announces a way to make screws on the lathe, illustrated by a threaded spindle mounted vertically in a tall frame at the centre of the sheet, with a T-headed control rod alongside.
Round plane and blades for the male thread
A round plane and two blades, each marked n, cut the male thread. Leonardo specifies that the plane's iron is set three or four times deeper in one than in the other, so successive passes bite progressively.
Guide for the female thread
At the left is a guide for forming the female thread, the counterpart to the male-cutting plane so that the two threads mate.
Instrument for drawing, female and male
The long bench-like device across the foot of the page is an instrument for drawing, shown in two details labelled female and male.