Mr. Quinn points to the bull's-eye glass and square nails as examples of the "hair-splitting authenticity" with which the Munkleys restored a house more than 160 years old.

They were made individually by blacksmiths. Square-head nails were made from the late 1700s until about 1830. Most were machine-cut and finished off by a blacksmith who squared the heads.

Each nail was made individually by a blacksmith. True square-head nails were made from the late 1700s until about 1830. They were machine-cut but finished by a blacksmith.