[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.
![[Larger plate.]](#3701448400155979539_plate39lg.png.id-4311245982822957505.wrap-0.html.html){kind=link}