Dating machine cut nails
Between 2d and 10d the nail length increases 0.25 inch (0.64 cm) for each penny designation.Beyond 10d there is no logical progression to the lengths and designations. They were usually made one at a time, and were consequently scarce and expensive.For example, a "ten penny nail" would have cost ten pennies per hundred. This designation is believed to go back to the time of the Roman Empire when a similar form of measurement for hand-forged nails involved a common Roman coin known as the denarius.Today the term penny only defines the length of a nail and has nothing to do with the price.These machines cut tapered pieces from flat iron sheet, then flattened the head.In rural areas, black-smiths continued to make nails from wrought iron right into the 20th century.
The diameter of the shank is determined by the type of nail.The protruding head allows the nails to be easily removed and the forms quickly dismantled once the concrete has hardened.The shank is usually designed to be round and smooth.Other nails may have a blunter point to prevent splitting certain woods.Chisel points, barbed points, needle points, and many others are sometimes used on specialty nails.