The Knapp or pin-and-scallop joint

The Knapp Dovetailing-Machine Co. was named after Charles Butler Knapp's dovetailing machine, which made Knapp joints, also known as the cove-and-pin joint or the pin-and-scallop joint. See the pictures accompanying the patents: click on Patents tab, above, choose a patent and from the resulting page, click on the "USPTO pdf" link under the patent image.

Mr. Knapp, who lived in Waterloo, WI, sold the rights to his machine to a group of investors, who set up the company in 1870 in Northampton, MA. Knapp was listed as co-inventor on an 1872 patent for improvements on the original design. That patent was co-invented by one Nathan S. Clement. Mr. Clement received an 1888 patent for improvements to the original invention.

The Knapp joint was very popular, especially in the 1870s and 1880s. It substantially reduced the labor required to make drawers. By 1900, the joint had fallen completely out of favor and the company disappeared. There would be considerable interest in a surviving Knapp dovetailing machine, but none are known to exist.

Information Sources

• Article found on the web, Mr. Knapp's Oddity, by Fred Taylor.
• Patent records provide corroborating dates and give inventor names and locations.
• The September 28, 1876 issue of The New York Times carried a multi-page listing of award-winners at the Centennial Exhibition. Knapp Dovetailing Machine Company won for their dovetailing machinery.
• Reports of the United States Commissioners to the Paris Universal Exposition, 1878": "Knapp Dovetailing Machine Co., Northampton, Mass. Machine for dovetailing cabinet and other wood work."