The slitting mill was a watermill for slitting bars of iron into rods. The rods then were passed to nailers who made the rods into nails, by giving them a point and head.
The slitting mill was probably invented near Liège in what is now Belgium. The first slitting mill in England was built at Dartford, Kent in 1590. This was followed by one near Rugeley at the once separate village which was called Stonehouse, but now called Slitting Mill, by about 1611,[1] and then Hyde Mill in Kinver in 1627. Others followed in various parts of England where iron was made. However, there was a particular concentration of them on the River Stour between Stourbridge and Stourport, where they were conveniently placed to slit iron that was brought up (or down) the River Severn before it reached nailers in the Black Country.
The slitting mill consisted of two pairs of rollers turned by water wheels. Mill bars were flat bars of iron about three inches (75 mm) wide and half an inch (13 mm) thick. A piece was cut off the end of the bar with shears powered by one of the water wheels and heated in a furnace. This was then passed between flat rollers which made it into a thick plate. It was then passed through the second rollers (known as cutters), which slit it into rods. The cutters had intersecting grooves which sheared the iron lengthways.[2]