1) In these mills, flat bars of iron were formed into plates between rollers and then passed between grooved rolls or ‘slitters’ to produce rod iron for nail-making.
The first slitting mills were introduced into England from the Continent at the end of the sixteenth century and they were established in Yorkshire during the 1600s which led to a considerable expansion of the nail trade. The first slitting mill in the Sheffield district was probably the one built for George Sitwell at Renishaw in the 1650s. The one at Masborough was recorded in 1678 and another at Wortley, next to the forge, was first mentioned in a lease in 1684. Further north a lease of 1665 granted Thomas Dickin of Colne Bridge liberty to erect, build and make use of a slitting mill … near the place where a corn mill … formerly stood. A slitting mill at Kirkstall near Leeds is said to have been built in 1676, and Thoresby said in 1714 that it had been erected for slitting iron into small Bars or Rods, by which Means there is a considerable Manufacture of Nails. When the lease of Wortley slitting-mill expired in 1738 the ‘utensils’ to be left there were listed as The Engine with 1 pair of cutters and 1 pair of Rolls, 2 Spanners, 1 Hammer, 2 pairs Furnace Tongs, 2 pairs Draw Tongs, 2 pairs Middle Tongs, 2 small Furgins, 1 Ringer, 1 Hook, 1 Chizel, 1 Weigh Beam and Scales with ˝cwt., 1 Binding Bench, 2 pairs Binding Tongs, 1 Pestle, Hams [sic] and Grease Dishes, 2 Furnace Hooks, 1 Coal Rake, 1 Box to Break iron on, 1 Box to put Cutters in, 3 Furnaces, 2 with Bars, one without. Rolling and slitting would often take place in the same mill and it was not unusual for the terms to interchange.