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.
[Illustration: 628.-649.]
=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.=