The donor states that it was used from the 1920s through to the 1940s; identical item on website dated to 1930s.
Measurement numbers from 1 to 180 degrees going both ways on the circular edge; "No 19 // THE L.S. STARRETT CO. // ATHOL. MASS. U.S.A." engraved on the protractor; "READ INSIDE SCALE // READ OUTSIDE SCALE" written in pen on a piece of tape on the handle
Inscribed on centre of dial: "L.S. STARRETT ATHOL, MASS. U.S.A. // PAT. APRIL 15, 1897"; metal indicator is calibrated 10 to 100 and 100 to 10; lid of box has, "Red - Labelled No. 107 STARRETT // Registering Speed Indicator // MADE BY".
Storage Room 0010
#2: cardboard box falling apart
Smithsonian National Museum of American History
A revolution counter. To count revolutions of the shafts that ran machinery, engineers used counters like this one. The manufacturer, L. S. Starrett Company of Athol , Mass., called the device a speed indicator, although it has no timekeeping apparatus. The steel counter has a flat handle on one side and a rotating cylindrical rod on the other. In between is a flat curved case on which a dial is mounted. Pressing the rod against a rotating shaft rotates it and advances the dial. The edge of the dial is divided into 100 equal parts, which are numbered from 10 to 100 by tens. Two different nozzles fit into the far end of the cylinder. The instrument fits in a red, white, and black paper box.
his counter is one of the many inventions of Laroy Starrett (1836-1922), who was born and raised on a farm in Maine. In 1880, having successfully patented and sold a meat chopper, as well as shoe studs and hooks, Starrett established a business in Athol, Mass., to sell drawing instruments and small tools. He applied for a patent for a speed indicator in 1895, and received it in 1897.
patent to L. S. Starrett Company when it was granted March 28, 1905. The device sold in at least three models. This is No. 104, which was particularly intended for high speeds. It was sold both directly by Starrett and through distributors of tools and steam engine equipment. This speed indicator is mentioned in Starrett catalogues into the 1930s.