Vintage Screw Thread L.S Starrett No.3 Micrometer
This Vintage Screw Thread L.S Starrett No.3 Micrometer was made by Starrett based in Athol, MA, in the USA. It is interesting in that the micrometer has a friction thimble, pointer tally, and lock, but sits in an old Moore & Wright (Sheffield, England) eyeglass style case. It also comes with a ‘C’ spanner.
This little object has been well loved by the Engineering lecturer/amateur watch repairer who owned it. He had quite a collection of old measuring devices and at some stage he obviously mixed up his Starrett with his Moore & Wright. This is easily done as both companies produced very similar looking micrometers on different sides of the pond.
There is a maker’s mark, seen in the image below, and it is inscribed D. Carman.
The no.3 micrometer was made as a machinists tool and is very similar to the original early 20th Century company version in design. This one dates to approx. the 1950s/60s.
The micrometer is approximately 11.5cm long and 4.5cm in height.
According to the Cambridge Dictionary:-
A Micrometer is a device for making very exact measurements or for measuring very small things
Micrometers use a calibrated screw to measure small distances. These measurements are translated into larger screw rotations, which enable the measurement to be read from a scale.
Micrometers are typically used in manufacturing, machining, and mechanical engineering.
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There is a nice article on the history of Starrett at the following website.