Section 37.—FASTENING WHEELS TO SHAFTS.

Besides the ordinary plan of shrinking them on while hot, the following are the chief devices in use:—

[634]. Square shaft and single key.

[635]. Square shaft and two keys at right angles; two keys should always be used for a square shaft, unless it has been machined to fit to the hole.

[636]. Round shaft and hollow key.

[637]. Round shaft and flat key.

[638]. Round shaft and sunk key.

[639]. Staked fastening, four keys, usually on flats cut on shaft, but better if slightly sunk into shaft.

[640]. Set screw. Cannot be depended on for any but light strains.

[641]. Taper pin.

[642]. Split pin; always used where a pin, bolt, or centre is liable to work loose.

[643]. Cotter and slot.

[644]. Screwed pin through shaft and boss of wheel.

[645]. Octagonal shaft of cast iron, with four keys, or the four keys may be cast on shaft.

[646]. Cotter or pin through side of shaft.

[647]. Large wheels are sometimes wedged with iron and wood wedges all round on a square or octagonal shaft having feathers cast on it.

[648]. Set screw, tapped half into shaft and half into wheel.

[649]. Screwed shaft, nut and clamping plates; used for emery wheels, grindstones, circular saws, and milling cutters.

[650]. Screwed end and nut, the hole in wheel being square, or round and fitted with key.

[651]. Gib head taper key.

[652]. Plain taper key.

[653]. Taper round pin.

[654], [655]. Split pins (round).

[656]. Cotter and split pin.

[657]. Cotter and nut.

[658]. Dovetail taper key, or fixing for projection, cutter or bracket.

[659]. Self-locking pin; cannot work out.

[660]. Split collar and ring fastening, sometimes used instead of a nut and screwed end; the inner ring is in halves.

[661]. Piston rod fastening.

[662]. Locking feather and wedge fastening, for rollers, &c., prevents end motion.

[663]. Railway chair key.