forming at least part of {HEAD ~ the periphery} of the motor member with an exterior diameter greater than that of {TAIL ~ the bore} of the jacket member 
forming at least part of { HEAD ~ the periphery } of the motor member with an exterior diameter greater than that of { TAIL ~ the bore } of the jacket member
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH