said coupling portion and said main cylindrical member have a pair of holes formed to correspond to each other, one of {TAIL ~ said pair} of holes having a tapered surface inclined with respect to {HEAD ~ said axial direction}, 
said coupling portion and said main cylindrical member have a pair of holes formed to correspond to each other , one of { TAIL ~ said pair } of holes having a tapered surface inclined with respect to { HEAD ~ said axial direction } ,
OTH 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 TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH