Dating square cut nails
The two numerals on their heads are the last two numerals in a year. Chicago: American Railway Engineering Association, . DATING NAILS Material The nails shall be made of iron or steel, galvanized with a coating of zinc (prime western, or equal) Figure 322 evenly and uniformly applied by the hot-dip process so that it will adhere firmly to the surface of the iron or steel.
They came into use when railways began to treat ties with preservative, as a way of monitoring which treatments worked best, and gradually went into disuse as wood preservative technology matured and other means of marking dates were introduced.¹ Still, some were driven as late as . Chemical Requirements (a) The sample shall be immersed in a standard solution of copper sulphate for one minute and then immediately washed in water thoroughly and wiped dry. If after the fourth immersion there is a copper-colored deposit on the sample, or the zinc has been removed, the lot from which the sample was taken shall be rejected.
To determine if missing nails were antique or if they have been replaced with modern nails, look closely at the shape of the hole and the color of the wood around it.
A nail may not be a noticeable style feature, but looking at them carefully can help you authenticate the age of a primitive or antique furniture piece before you buy.
Like restorers of historical buildings, you can identify the period by the technology used to create the nails and unlock the past of furniture.
Around 1880, a machine was invented that produced a round nail drawn from a piece of steel wire and formed with a perfectly circular, stamped head and a sharp, cut point.
Cabinetmakers continued to use cut nails into the start of the 20th century until stockpiles were used up, so you may find either type of nail in furniture between 18.