Sheet of machines: a six-stone mill, a segmented bombard and a screw
Mills, a Po river waterwheel, a bombard built of screw-together pieces, and a screw-jack
A working sheet mixing milling, artillery and lifting devices. At the upper right a large circular mill with six grinding beds is meant to be turned by a horse over a run of 16 braccia, while a separate waterwheel is noted as the kind of mill-wheel used on the river Po. In the centre and left are pieces of a bombard that can be assembled from as many as forty screw-together segments with male and female threads, and a device for twisting or bending trestles. A screw-jack (marked a) carries its nut in a wooden block and needs a pivot below so it can turn easily.
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Mill with six grinding beds
The upper-right drawing shows a large horizontal ring carrying six millstone housings — a mill with six palmenti. It is arranged to be driven by animal power.
Horse drive over sixteen braccia
A driving bar is labelled with a span of 16 braccia and the note that a horse is to be harnessed here, walking its circuit to power the mill.
Waterwheel of the Po mills
A wheel drawn partly immersed in a current of water is identified as the type of mill-wheel used on the river Po, driven directly by the flow.
Bombard built of forty screw-together pieces
A gun barrel is shown as a set of threaded segments. By this means, the note explains, one can make a bombard of 40 pieces that behaves as though of one piece, the joints alternating female and male threads.
Device for twisting the trestles
A separate mechanism is captioned as the way in which the trestles are twisted or bent, a rig for forcing timber supports into shape.
Screw-jack with its nut in block a
The screw carries its nut in the piece of wood marked a. Leonardo notes that the screw must have a pivot underneath so that it can turn easily.