American Levels and Their Makers
Hall & Knapp was one of the predecessor companies of Stanley Rule & Level. It was founded in 1853 and merged with the A. Stanley Co. in 1857. Hall & Knapp was probably the earliest full line level manufacturer in Connecticut with the H. Chapin Co. close behind. They are believed to have had at least 25 different models in their product line, including 3 cast iron levels. The level pictured above was not one of the models in the product line. No other example of this clearly marked level has been found to date.
The stock is highly figured Brazilian rosewood, 20" long, and of slightly smaller cross section than other levels of the period. Hall & Knapp had two other levels of similar size in their line (the #11 ½ and #12). All of the brass fittings are nickel plated and it appears that the nickel was chemically deposited as opposed to the electroplating method used later. The nickel plating would be enough to set this level apart from the rest of the product line, but no other level of any size had the same configuration of plumb and level vials. The bottom is covered with a full brass plate (nickeled).
Hall & Knapp's round side plates hold the spirit vial on a little shelf attached to the back of the plate. Identical side plates (without nickel plating) are found on some of their full size levels. Hall & Knapp's side plates are different from others of the period because of their thickness. The normal side plate of the period was cast brass but the Hall & Knapp plates were punched from thin sheet brass. This level is believed to be unique and may be some sort of a presentation piece.