[2443]. Mutilated screw and nut.

[2444]. Nut lock, by a fixed lug and split pin.

[2445]. Coned bolt for securing and keying two parts of a machine in exact relation.

[2446]. Double-nutted bolt, easily made of round iron.

[2447]. Lever and compound nuts to obtain great leverage on a screw, as in a press; one nut arm is used as a fulcrum by which the lever forces the other round. Stepped pawls are used to prevent the first nut being loosened while moving the second.

[Larger plate.]

[2448]. Screw gear to operate three worm wheels in the same direction, for chucks, &c.

[2449]. Screwed stay bolt, as a distance stay for boiler plates, &c.

[2450]. Screw eye and handle nut.