Dating old buildings
As explained earlier, the first cut nail machines replicated the handmade nail - the square tapered nail with a rosehead.
Because the process still involves a man (or woman) presenting a strip of metal to a machine, the resulting nail is necessarily imprecise - that is each nail can look a little different to the next one.
The wood fibres would often swell if damp and bind round the nail making an extremely strong fixing.
In Tudor times, we have evidence that the nail shape had not changed at all as can be seen by the nails found preserved in a barrel of tar on board the 'Mary Rose' - the Tudor flag ship of Henry VIII built in 1509 and recovered from the mud of the Solent in 1982.
Thinner timbers were being used in construction and other forms of fastening were becoming available if a strong fixing was needed.
By the start of the 1900's, the first coils of steel round wire were produced and quickly machines were designed to use this new raw material. The inquiry will have two stages: Investigation and Corroboration. Investigation Tracking down clues directly connected with the physical structure, architecture, or construction.But don't overlook trace evidence of daily life, relationships, and events on site or nearby.The first automatically produced wire nails with no human intervention other than to set up the machine immediately showed that this was the way to produce a cheaper nail.The fact that the nail had a round parallel shank that had up to four times less holding power didn't matter so much.