Screw-cutting tools, a weighted wheel and lifting gear
Taps and instruments for cutting screw threads, with a scoop-crane and a heavy flywheel
The sheet gathers several mechanical studies. At upper left are tools for cutting screw threads: a large tap for forming the female thread (nut) and a bench instrument for cutting the screw itself. A large wheel at the foot of the page is to be loaded with bricks around its rim to make it heavier, while a long pivoting arm with a scoop lifts material from a walled pit at upper right; a short note labels the 'guide of the lever.' Further mechanisms drawn on the sheet are not covered by the transcription.
On this page
Tap for threading a nut (madrevite)
The large tool at upper left is a tap for cutting the internal thread of a nut. Leonardo's note reads simply 'to make the nut for the screw,' pairing the tool with the screw it will mate.
Instrument for cutting a screw
A device for threading the male screw. The captions describe the 'way to make a screw' and how the cutting-blade (lancetta) of the screw must be set.
Weighted wheel
A large wheel at the foot of the sheet is to carry bricks around its rim so that it becomes heavier, increasing its mass and steadying its turning.
Guide of the lever
A short note on the right labels the 'guide of the lever,' referring to the tall pivoting arm and scoop drawn nearby.
Scoop-crane lifting from a pit
At upper right a long pivoted arm carries a curved scoop that lifts spoil out of a walled pit, a device for excavation and moving heavy loads on site.