Dating old nails
Most date nails are steel, though many are copper, aluminum, malleable iron, or brass.Lengths run from a paltry 3/4" up to 3", with shank diameters running from 1/8" up to 5/16".
The NYC bought its 1910-1913 nails from American Steel & Wire Co., its 1914-1915 nails from Jones & Laughlin, its 1916 nails from American Casting & Manufacturing, etc.Add to that the nails which tell wood, treatment, and other information, and toss in all date nails used in poles and other timbers, and the total number of different nails from this continent easily exceeds 3,500. This one was manufactured to be 2 1/2" long (it was cut a little short), and is made from steel wire 1/4" in diameter. Note the crude, somewhat faint diamond on the shank to the left of the anchor markings.It might look more like a horizontal blob on this nail.Each railroad conducted its own experiments, so the nails used on one railroad will not be like those on other lines.For example, compare the Lehigh Valley with the New York Central: The LV 11 is the same style nail as the NYC 11: square head & shank, indented numbers. The NYC stuck primarily with square nails while the LV used round nails.