Elements of a Machine: Shafts and Bearings
Pen sketches of horizontal axles running in framed journal bearings, with a small assembled mechanism
The sheet carries a scatter of rapid pen sketches of mechanical parts, catalogued by the Biblioteca Reale as "Elementi di una macchina" (elements of a machine). At upper centre are repeated studies of a horizontal shaft or axle passing through upright framed supports and a raised collar, redrawn to test the arrangement of its journal bearings. To the right a more finished component is worked up in perspective on a base, with a further hatched structure sketched at the lower right corner. Faint red-chalk offsetting and stains cross the paper, but no continuous text accompanies the drawings.
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Horizontal shaft in framed journal bearings
Twin sketches show a round horizontal shaft carried between upright bracket-like supports, with a thickened collar or bearing near its middle. Leonardo redraws the same member to study how the axle is seated and held while free to turn.
Shaft passing through a boxed housing
A lower variant sets the shaft into a square box or bearing block seen in perspective, the axle emerging from one face. The sketch probes how a rotating member might be housed within an enclosed support.
Assembled mechanism drawn in perspective
At the right a taller assembly is built up on a base, with angled arms rising to a small block, and beneath it a densely hatched structure. These sketches move from isolated parts toward a working combination of components.