A pocket comparator is an optical device for measuring and inspection comprising a loupe and a reticle."The Pocket Comparator - A New Optical Measuring Instrument". in: Electrical Engineering (Volume 69, Issue 3, p. 220) March 1950 https://ieeexplore.ieee.org/document/6433729/ The instrument was developed and manufactured by the Bell & Howell Company, but similar instruments of other names are made by other manufacturers." by Marcus Bowman Crowood, 31 August 2015, Crafts & Hobbies"Low price measuring magnifier uses real glass reticle", Journal of the Franklin Institute, 1955, Vol. 259(6), pp. 516–516 [peer reviewed journal]
It is used for: Linear measurements in fractions of an inchCharles C. Ryerson and Anthony J. Gow: Ship Superstructure Icing: Crystalline and Physical Properties in: US Army Corps of Engineers® Engineer Research and Development Center (August 2000) p. 14van Altena, W. F., Low-luminosity members of the Hyades cluster. Astronomical Journal, Vol. 71, p. 482–512 (1966)I. B. A. Menown, G. MacKenzie and A. A. J. Adgey, Optimizing the initial 12-lead electrocardiographic diagnosis of acute myocardial infarction, European Heart Journal (2000) 21, 275–283 Circular measurements in fractions of an inch Radius measurements Angle measurements Narrow line width measurementsDEPARTMENT OF THE ARMY EM 1110-2-2002 U.S. Army Corps of Engineers: EVALUATION AND REPAIR OF CONCRETE STRUCTURES p.2-11 https://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-2002.pdf Circular measurements in decimals of an inch Linear measurements in inches Linear measurements in millimeters
Measurements are performed by bringing the surface of the reticle as close as possible to the work inspected.The Pocket Comparator: A New Measuring Instrument, in: INDUSTRIAL QUALITY CONTROL VOL.6 NO.5, March 1950 pp. 22-23
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