Cutting a screw-thread: drills, taps and a die

A drill for starting the hole

A drill labelled h t r – m f n – l g o is drawn at the top; the note explains that the width r o equals the tooth g t, whose base is the hole made by the drill.

A tapered square screw

A conical screw is described as 'a square screw, somewhat pyramidal,' that is, tapered — the form of the tap used to begin the thread.

Cutting and casting a screw and its nut

The long central note explains how concentric circles mark the base and tips of the teeth, how a triangular iron m f n and paper templates size the female thread, and how to cast the screw first in tin and then in brass or bronze so as to 'avoid the annoyance of the file.'

Latin verbs with conjugation endings

At the foot, written upside down, is a short conjugation list — amo/-as, diligo/-is, zelo/-as, adamo/-as, audio/-is — grouped under 'for to love' and 'for to hear.'

Figura di trapano, con: h t r – m f n – l g o

Trapano a tre teste, con:

Vite conica:

Due tavole forate, con:

Tavola da forare con due cerchi concentrici:

Foglio capovolto.

Figure of a drill, with: h t r – m f n – l g o

Drill with three heads, with:

Conical screw:

Two perforated plates, with:

A plate to be bored, with two concentric circles:

Sheet turned upside down.

Cutting a screw-thread: drills, taps and a die

On this page

A drill for starting the hole

A tapered square screw

Cutting and casting a screw and its nut

Latin verbs with conjugation endings