Reversed screw with its stop, and coupled rods
A left-handed screw labelled at the lower left, with rod couplings and a winged fitting
The fragment carries several mechanical studies in pen. At the lower left a vertical screw — a reversed, left-handed screw — is set in a block, and the transcribed word labels its stop or catch. Across the top run horizontal rods joined by rings and a hooked coupling, while at the right a central screw is flanked by two broad curved wings. An old inventory number is inscribed near the centre but is not transcribed here.
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Reversed screw with its stop (fermo)
In the lower-left corner a vertical screw threads through a block on a base. The transcribed label marks the fermo, the stop or catch that arrests the screw so that its reversed thread holds against turning.
Rods joined by rings and a hook
Along the top, horizontal rods are linked by rings and a hooked coupling, forming a chain of connected members. The drawing studies how the rods are tied together at their ends.
Screw flanked by two curved wings
At the right a central threaded shaft is set between two broad, curving wing-shaped elements. The fitting appears to be a mechanical component seen in outline, its use left unstated.