Abstract: A die and method of assembling a high torque capacity metal spool. The spool comprises a cylindrical barrel, a pair of flanges and a pair of flange hubs. The die includes a support member and a curling member that is adapted to move relative to the support housing. The die is adapted to be driven towards a matching die to press a spool therebetween. Each curling member includes an annular curling face which is adapted to curl and compress metal edges of the cylindrical barrel, the flanges and the flange hubs into tightened curls. The tightened curls secure the cylindrical barrel with the flanges and flange hubs. Each die further includes a plurality of nibs carried by the support housings which project outward from the curling face of the curling member after the tightened curls have been formed to swage a plurality of detents into the tightened curls of the spool. The resulting detents in the metal spool provide for increased torque transfer between the flanges, the flange hubs and the cylindrical barrel.