Geared Mechanisms with a Screw
A screw that 'goes in front' at the right, with two further devices marked 6-6 and 6 7-4-2
The verso continues the mechanical studies of the recto with several framed devices combining screws, gears and linkages. A figure at the right carries the note that 'this screw goes in front', while two further mechanisms are annotated only with strings of numbers. The page reads as a set of alternative machine arrangements.
On this page
Screw at the right
A device at the right is built around a threaded screw. Leonardo's caption specifies its placement — 'this screw goes in front' — indicating the working orientation of the part within the assembly.
Device at the left (6-6)
A mechanism at the left is marked with the numbers 6-6, most likely keying matching parts or measured dimensions of the device.
Lower device (6 7 - 4 - 2)
A further device below carries the numeric annotation 6 7 - 4 - 2, again apparently recording measurements or the counts of its members rather than a written description.