Briefly, a date nail is a nail with the date stamped in its head. I concentrate primarily on the nails used by railroads.
Date nails were driven into railroad ties, bridge timbers, utility poles, mine props, and other wooden structures for record keeping purposes.
Then the nails were driven into ties either at the treating plant, to indicate the year of treatment, or at the track, to indicate the year the tie was laid.
The nail heads can be round, square, diamond, pentagon, as well as other rarer shapes.Go to the Photo Album for more pics of nails in ties.' Date nails were manufactured by steel companies on high speed machines, even in the early years.If a railroad wanted to use date nails, they would order the kind of nails they wanted (for instance, a 2 1/2" x 3/16" steel nail, round with raised numerals "34").For these companies keeping track of only a few thousand ties was far more economical and accurate than tracking several million ties.By the early 1920's, however, most of these railroads had returned to the practice of placing nails in every treated tie.
Wherever treated ties come into use, date nails are not far behind.