Fig. 15 points out an ordinary hexagonal nut for a stop-ring, which is indicated by Fig. 16. This kind of nut is much used by engineers, who consider it a sort of safety nut, by reason of the set-screw in the ring having some tendency to prevent the nut unscrewing through straining or vibration of the machinery while at work.

Nuts of this character are made by cutting partly through a bar and doubling or trebling the bar, and thoroughly welding the layers while in that relation. AVhile the lump is still attached to the bar, the opening is made by a punch driven through at right angles to the layers, and the opening is then drifted to any required diameter; after which the nut is cut from the bar, and another doubling and welding is effected to produce another nut. When the desired number is obtained, the outside of each nut is shaped while at a welding heat.

The short cylindrical portion named the stem is formed sometimes by cutting off the six corners or apices by turning-tools, and at other times by cutting off the pieces while hot upon the anvil, which is a much quicker process. The nuts are marked while cold by means of a chisel, which is driven in at the spot which marks the required forged length of the stem; they are then heated to a light yellow heat, and the pieces are cut from the stems with a trimming-chisel and light hammer. Each nut is placed upon a mandril, and while supported by an angular-gap tool in the square opening of an old-fashioned anvil, the chisel is driven in at the marks to the distance required; after which the nut is taken from the mandril and placed with the face-side upwards upon the anvil; while the nut is in this position and gripped by a tongs with large jaws, the chisel is driven down to meet the extremities of the six incisions previously made, and the scrap-pieces are thus cut from the stem in an easy manner.