Alternatively, {HEAD ~ the shaft} could be provided with a plurality of keys or keyslots, and the disc 51 provided with a single keyslot or {TAIL ~ slot} engaging member 
Alternatively , { HEAD ~ the shaft } could be provided with a plurality of keys or keyslots , and the disc 51 provided with a single keyslot or { TAIL ~ slot } engaging member
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH