Forged Square-Neck Door Bolt and Nut, Threaded with a Screw-Plate (Moxon, 1677)

"The Shank of the Screw for Doors and many other purposes must be Forged square near the Head, because it must be let into a square hole that it may not twist about when the Nut is turned about hard upon the Screw-Pin."

Take a square iron bar as near the size of the head as you can. At a flame (white) heat lay the shank length flat on the near side of the anvil and hammer it down to thickness; do not strike over the edge or you cut the iron. Reheat, turn it, and hammer the other two sides close up to the head.

Hammer down the corners of the part meant for the thread and round it. Set the chisel at the head thickness, strike half through, turn and cut each side half through until it comes off. Square the shoulder: reheat, grip in square-nosed tongs, set the shank in the vice with the shoulder on the jaws, and hammer the head.

Forge a nut blank from the bar. Harden the point of a steel punch of the hole's size (no tempering: the hot iron softens it). At a blood-red heat punch from one side until the far side bulges, turn it, set it flat, and punch through over the hole of a bolster. Dip the punch in water whenever it changes colour. Let forged work cool on the floor or hearth; never quench it.

File the shank and head, file the pin round, and taper its end by the depth of the screw-plate's threads. Find the screw-plate hole the pin just slides through, turn the pin in it, and file off the marks it cuts: the pin is then true. Set the bolt head down in the vice, press the next smaller hole (groove diameter equal to the pin) hard down on it, and turn the plate evenly.

Fit the tap to the round hole of the nut; it must match the pin (try it in the same screw-plate hole). Set the nut flat in the vice and turn the tap hard round by its handle, or by the square hole near the screw-plate handle, until it cuts the thread.

From Joseph Moxon, **Mechanick Exercises, or the Doctrine of Handy-Works** (1677), Smithing, Numb. I pp. 10-11 and Numb. II pp. 29-31 (checked on the archive.org scan mechanickexercis00moxo). He gives no sizes or nut shape; the metric example and the tool heads are ours.