Hubbing Retainer. A tube-like collar in which a hub and a die blank are placed in a hubbing press. The retainer holds the hub and the die blank in register while the pressure is applied to sink the design. Often the die blank is a cone blank or dome blank and the hub would not seat squarely without a retainer. Also it prevents, somewhat, either from shattering should too much pressure be applied. The height of the hubbing retainer, obviously, had to be less than the combined height of the hub and the die in fully hubbed position. An experienced operator can use a V-block in place of a hubbing retainer.