Faint sketch for laying out a screw thread
Rod, banded rectangle and strip with untranscribed mirror-script
At the top of this otherwise blank folio (numbered 104) are faint pen figures: a slender upright rod or cylinder, a rectangle ruled into many equal parallel horizontal bands, and a short separate strip. The forms read as the layout for marking out a screw thread. Several lines of Leonardo's mirror-script accompany the figures; that writing is not included in this bundle and is not transcribed here.
On this page
Figures for marking a screw thread
A slender upright rod stands beside a banded rectangle and a short horizontal strip. Together they read as the layout for wrapping a divided paper around a rod to set out the turns of a screw. No dimensions are legible.
Rectangle divided into equal parallel bands
The rectangle is ruled into many equal parallel horizontal bands, a division of a surface into equal parallel parts. A short strip beside it appears ruled with slanting lines.