Hall's success, in his telling of the story, came about because of his determination to go his own way with a radical redesign of the press, which employed a doughnut-shaped die surrounded by shrink-fit steel sleeves (the belt) which confined the sample chamber and two curved and tapered pistons which pressed on the sample chamber. He "bootlegged" the machining of the first hardened steel version of this press, which showed some promise, and eventually got management to approve the construction of it in the tougher, much more expensive Carboloy (tungsten carbide dispersed in cobalt, also known as Widia). However, his experiments were "relegated" (Hall claimed) to a smaller, antique, leaky 400 ton press, rather than a more expensive and new thousand ton press used by other members of the team.