Sizing Machine

A textile sizing machine mechanically applies size, a starch-based coating, to warp yarn before weaving, stiffening and smoothing the individual threads so they can withstand the repeated friction and tension of the weaving process without breaking. Sizing had long been done by hand, but the English weaver William Radcliffe and his assistant Thomas Johnson mechanized the process during the early nineteenth century, inventing a sizing machine that applied size to an entire warp at once rather than yarn by yarn, a development that, together with dressing frames, allowed the power loom to be run at much higher speeds than hand-sized warp could support. The sizing machine became a standard fixture of the mechanized weaving shed alongside the power loom, and mechanized warp sizing remains a standard preparatory step in industrial weaving today.