High Speed Indicator, 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.

A mark on the dial reads: THE L. S. STARRETT CO. (/) ATHOL, MASS. U.S.A. Another mark there reads: PAT. APR.13.97 (/) MAR.28.05

This 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.

Stafford P. Walsh of San Francisco, Ca., improved on the instrument, assigning his 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.


L. S. Starrett, “Speed-Indicator,” U.S. Patent 580,432, April 13, 1897.

S. P. Walsh, “Speed-Indicator,” U.S. Patent 786,073, March 28, 1905.

“Laroy S. Starrett,” National Cyclopaedia of American Biography, 18, New York: J. T. White and Company, p. 428.

L. S. Starrett Company, Catalogue, Athol, Mass., about 1937, p. 192.

Date Made: ca 1910

Maker: L. S. Starrett Company

Location: Currently not on view

Place Made: United States: Massachusetts, Athol

Subject: Mathematics


See more items in: Medicine and Science: Mathematics, Counters, Science & Mathematics


Exhibition Location:

Credit Line: Edith R. Meggers

Data Source: National Museum of American History

Id Number: MA.335271Catalog Number: 335271Accession Number: 314637

Object Name: counter, analogcounter

Physical Description: steel (overall material)paper (overall material)Measurements: overall: 2 cm x 14.3 cm x 5.4 cm; 25/32 in x 5 5/8 in x 2 1/8 in

Guid: http://n2t.net/ark:/65665/ng49ca746a5-1583-704b-e053-15f76fa0b4fa

Record Id: nmah_690549

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