Wheel-driven machine for grinding points on a grindstone
A geared mechanism where one wheel presses the points onto the mill, needing no spring
A large mechanical study built around a long horizontal shaft carried in bearing-blocks, a great toothed wheel, a solid drum, and a big disc wheel turned below by a long crank arm, with several subsidiary sketches of the individual parts. A note titled the 'larger drawing with the wheels' explains that wheel a, turned inward, itself weighs the points down onto the grindstone so that no separate pushing spring is needed, and that wheel b is driven from wheel a. A mutilated fragment survives in the left margin. Further mechanical detail is drawn that the transcription does not cover.
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Wheel a loads the points onto the grindstone, sparing a spring
Leonardo arranges the mechanism so that wheel a, turned inward, presses the points down against the grindstone (mola) by its own action, so that no additional spring is needed to push them. When the points then turn downward to be finished off, wheel b is turned from wheel a. The note is headed the 'larger drawing with the wheels'.
Long shaft, toothed wheel and crank-driven disc
The sheet is organized around a long horizontal shaft mounted in blocks, meshing with a large toothed wheel and a solid drum, while a big disc wheel below is driven by a long crank arm. Smaller studies at the sides work out the individual bearings and linkages. These drawings carry the working of the machine beyond what the note describes.