According to Robert Flynn in his Lizzie Borden and the Mysterious Axe (King Philip Pub. Co., 1992), it “is impossible to conclusively determine the size of an axe or hatchet head by measuring the width of marks and incisions.” Further he states, after a careful analysis of the evidence and testimony that “the hatchet found on the roof the Crowe Barn [June 14, 1893] was in all probability the murder weapon.”
From the Emery Scrapbook, owned by Mr. Flynn, we are shown this news item, dated June 15, 1893:
Here is a collection of various hatchets, axes, and interesting implements culled from the 1897 Sears, Roebuck Catalogue. Who knew there were so many different kinds of chopping tools?