Out Of The Blue Artifacts A Library of a lifetime of collecting
A Surveyors Hanging Nail.
Made from steel with plastic coated copper shotfiring wire. Size 1 1/2″ x 1/2″ inches.
A series of these nails were knocked into the roof timbers down the length of the roadway and heavy objects were attached to the wires and dangled from them, surveyors would line them up to make sure the roadway was being driven in a straight line and direction.