![]() Type A nails have burrs on the diagonally opposite edges, while the type B nails have both burrs on the same side because the metal was flipped for each stroke. By carefully examining the edges for evidence of these burrs, it is possible to distinguish between the earlier type A nails and the later type B nails. “Cutting the nails leaves a small burr along the edge as the metal is sheared. Nails made by this method are known as type B nails. With the resulting nails thus all oriented in the same direction, it became possible for the same machine to automatically grip each nail and form a head in a continuous mechanical operation. With the cutter set at an angle, every nail was sheared off to a taper. “By the 1810s, however, a more effective design for a nail making machine was developed it flipped the iron bar over after each stroke. This type of nail was made until the 1820s. At first, the heads were typically made by hand as before, but soon separate mechanical nail heading machines were developed that pounded a head on the end of each nail. The taper of the shank was produced by wiggling the bar from side to side with every stroke. The earliest machines sheared nails off the iron bar like a guillotine. “Between the 1790s and the early 1800s, various machines were invented in the United States for making nails from bars of iron. Visser’s description of cut and wire nails: L-head nails were popular for finish work, trim boards, and flooring. The remaining smaller piece would be inserted into a hole in a “nail header” or anvil and with four blows of the hammer, a shallow pyramid shape known as a rosehead would be shaped on the side opposite the point, the nail “head.” The most common head shape was the rosehead however, broad “butterfly” (with two roughly equal triangular flanges), or narrow L-heads (with a single flange, producing an overall shape of an elongated “L”) also were crafted. The pointed rod was reheated and cut off. A blacksmith would then reheat the rods in a forge, cut off a length and hammer all sides reshaping the rod into slimmer and slimmer profiles, with one end sharpened to a point. They left behind 7 tons of nails at the fortress of Inchtuthil in Perthshire.Įarly wrought iron nails were made by heating iron ore with carbon to form a dense mass of metal which was fashioned into square rods and left to cool. Any sizeable Roman fortress would have its ‘fabrica’ or workshop where the blacksmiths would fashion the metal items needed by the army. In Great Britain, early evidence of large scale nail making comes from Roman times 2000 years ago. Bronze nails found in Egypt have been dated to 3400 BC. Nails may seem like a relatively modern and key material for frame construction however, they have been in existence for thousands of years.
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