Spring-Wound Reels and Bobbin Details
Tooth heights, lead-weighted reels, steel springs tempered like needles, and two-piece bobbins
The page shows two large circular reels seen face-on, each with a square lead ('piombo') centre, together with detailed studies of spring-wound machine elements. The notes give dimensions: a b is the height of a tooth, b c the thickness of three threads, and c n the diameter of one oncia of such a wheel. Materials and parts are labelled and specified, including steel springs tempered like needles, tin plate ('tola'), and an iron a b on which the threads n m are wound to leave them hollow, with a bobbin fitted in two pieces. A closing note gives preferred spacings in once for a hollow soldered tube.
On this page
Dimensions of the toothed reel
The note fixes the proportions of the reel: a b is the height of a tooth, b c is the thickness of just three threads, and c n is the diameter of one oncia of such a wheel.
The iron a b and the two-piece bobbin
a b is identified as the iron on which the threads n m are wound so as to leave them hollow, with the bobbin fitted onto it in two pieces.
Steel spring tempered like needles
A caption beside the central figure specifies steel for a spring, tempered in the manner of needles. Nearby labels mark the lead ('piombo'), the spring ('molle'), the tin plate ('tola') and a pair of springs.
Spacing of the hollow soldered tube
The closing note prescribes that a b be a space of one oncia, though 2/3 of an oncia is better; a hollow tube is to be made through which the tin-plate wire passes, soldered with tin solder, with 1/2 oncia better still.