An externally threaded retaining nut 18 is screwed on a downstream threaded part 19 of the cylindrical portion 12 of the inner face 6 of the first shaft 1 and comprises a collar 20 which, on tightening, bears on {HEAD ~ a radial face} 21 of {TAIL ~ the first shaft} between the cylindrical portions 12 and 13 
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An externally threaded retaining nut 18 is screwed on a downstream threaded part 19 of the cylindrical portion 12 of the inner face 6 of the first shaft 1 and comprises a collar 20 which , on tightening , bears on { HEAD ~ a radial face } 21 of { TAIL ~ the first shaft } between the cylindrical portions 12 and 13
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH