The barrel back is made with particular specifications that our colonial cabinetmakers engineered in the first - to second quarter of the 18th century. The boards have a thickness of 5/16", and are nailed with hand forged rose headed nails, made by my friend Doug Schlicher of Woodbury, Ct.,- a professional actor by trade, this has been his part time gig - who since 1980 has made literally hundreds of thousands of nails for many historic sites, businesses and individuals ( yes, just himself ! ) of all 'period' types and sizes, there are only four - Rose heads, T-heads, Butterfly heads, and L heads. They are spaced 1-1/4" apart. I have an original remanent 18th century barrel back example of this for study. >