Gilling is achieved using a machine called a gillbox. This machine helps to straighten and improve the parallelization of the fibers, to provide further mixing, and reduce the fluctuations in the linear density of the sliver.

A number of slivers (doublings) pass between the back rollers (or feed rollers), merge into one sliver, and are progressively penetrated and held between pins mounted on the fallers. Upper and lower sets of intersecting fallers move forward towards the front rollers (or delivery rollers) at a slightly higher linear speed than the surface speed of the back rollers. This speed difference applies tension to the sliver.