Thursday, June 2, 2011

Nailing the Date

As we excavated further and further we began to accumulate a large mass of iron nails and fittings of seemingly different types. Some seemed more modern and others, less so. I recalled that in a previous field school at Wilder Ranch in Santa Cruz County (Link to site group page: I had used some basic information about the history of nail making to date a collapsed farm shed and several of the workers' cabins.

I reviewed our old site website to see if we had some of the resources I used posted but couldn't find them, so instead opted to google it. What I did find was an overview of nail-making history and its applications. I wanted to see if I could give everyone an overview of this approximate dating technique.

There are four basic classifications for identifying nails: Hand-Wrought, Type A Cut Nails, Type B Cut Nails, and Wire Nails.

Hand-Wrought Nails were manufactured entirely by hand, by a blacksmith in a process that started with a square, iron rod. After heating this rod, the smith would hammer the end of the softened metal on all four sides to attain a taper. The smith would then cut a portion of the rod to be the nail and create the head with several glancing blows. These nails were popularly used prior to 1800.

A rough picture of the product would look like this:

The second kind of nail was the Type A cut nail which appeared in the 1790's with the invention of various cutting machines. These machines would automatically taper the nail by wiggling it with each cut and cut it from a square iron rod in a guillotine-like fashion. They were popular from the 1790's to about the 1830's These nails looked something like this:

Around 1820, new machines were developed that cut the taper at an angle using an angled chopper instead of the guillotine style. Instead of wiggling the iron rod, this machine would flip the nail at each chop. These nails made similarly to the Type A, but with improved efficiency are called Type B cut nails. Type B cut nails were popular from 1820-1900. They are similar to the picture below.

Around the turn of the 19th century, a new method for creating soft steel emerged called the Bessemer method. Iron fell out of favor as it was prone to rusting and steel wire nails were produced in factories after this date. Wire nails are currently in use today and look like this:
By 1886, 10 percent of all nails used in construction were soft steel wire nails. By 1892 more than half of all nails were wire, and by 1913, 90% of all nails used were wire cut.

I hope this entry can prove useful to future catalogers!



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