The L.S. Starrett Company was founded by Laroy S. Starrett 1880 in Athol, Massachusetts to produce the combination square that he had invented and patented three years earlier.

In the 1850's Samuel Colt had revolutionised the gunsmithing industry with standardisation and interchangeability of parts. Laroy Starrett brought the same manufacturing standards to bear on toolmaking and established a reputation so solid that the words 'quality' and 'Starrett' remain virtually synonymous to this day.

The combination square along with several other Starrett inventions have since been widely copied, but not, as yet, by anyone who can achieve Starrett's consistent accuracy and reliability for less money.