Nut, 3/8in x 26tpi, half height lock nut

Nut -3/8in x 26TPI x 1/4in tall, zinc plated (ea), thin lock nuts  BSCY / CEI. Norton featherbed engine to engine plate stud nut
Original part number
E3224A -  nut]
Original Norton part numbers: E3224A, 13968; 18942; 067590,  22617
Original AJS Matchless part numbers: # 000003 or STD 3
Original Royal Enfield part numbers: FC49A, 26521, 26995, 26996, 29854, 42440
Original BSA part numbers: 011706 (1-1706), 020046 (2-46), 020449 (2-449),  544306
Original Triumph part numbers: S1-52 (210001052), 370076 (W76), 604261 (D4261), 828987 (F8987)