Pocket comparator
Bell & Howell Pocket Comparator
A Pocket comparator is an optical device for measuring and inspection comprising a loupe and a reticle.[1] The instrument was developed and manufactured by the Bell & Howell Company, but similar instruments of other names are made by other manufacturers.[2][3]
Reticle of Bell & Howell Pocket Comparator
Typographer Henri Friedlaender at work. Note Pocket Comparator at 01:10 .
It is used for:
- Linear measurements in fractions of an inch.[4][5][6]
- Circular measurements in fractions of an inch.
- Radius measurements.
- Angle measurements.
- Narrow line width measurements.[7]
- 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.
References
- ↑ The Pocket Comparator - A New Optical Measuring Instrument. in: Electrical Engineering (Volume:69, Issue:3, p.220 ) March 1950 http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6433729&url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6433729
- ↑ Screwcutting By Marcus Bowman Crowood, 31 Aug 2015 - Crafts & Hobbies https://books.google.co.il/books?id=xRWbCgAAQBAJ&pg=SA2-PA86&dq=%22Pocket+comparator%22&hl=en&sa=X&ved=0ahUKEwiF_OT_6u_JAhXISBQKHX9JCrkQ6AEIVjAK#v=onepage&q=%22Pocket%20comparator%22&f=false
- ↑ Low price measuring magnifier uses real glass reticle, Journal of the Franklin Institute, 1955, Vol.259(6), pp.516-516 [Peer Reviewed Journal]
- ↑ Charles 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. 14
- ↑ van 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
- ↑ DEPARTMENT OF THE ARMY EM 1110-2-2002 U.S. Army Corps of Engineers: EVALUATION AND REPAIR OF CONCRETE STRUCTURES p.2-11 http://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-2002.pdf
- ↑ The Pocket Comparator: A New Measuring Instrument, in: INDUSTRIAL QUALITY CONTROL VOL.6 NO.5, March 1950 pp. 22-23
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