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Scale Information This Section Updated Regularly Click REFRESH on your browser if pages seem unchanged  Sphere Research Corporation 3394 Sunnyside Rd. West Kelowna, BC, Canada V1Z 2V4 Phone: +1 (250) 7691834 FAX:+1 (250) 7694106 A great source for test equipment, repairs, calibrations, useful metrology information, and of course, SLIDE RULES! Want something? email us! Our FAQ !! Answers to all those questions. Visit our amazing document server. Quotes & SciFi to Ethics & Business. Just SCROLL DOWN to see everything! 
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Slide Rule Scales To get the best use out of a slide rule, you need to understand what the individual scales can do. Slide rules started out life with simple scales for multiplication and division, added squares and square roots, cubes and cube roots, then expanded into exotic log scales, trig functions, special purpose computations and different log bases.
Some Common Slide Rule Scale Variations: Mannheim (or Simplex) Slide RulesOriginal Mannheim rules had only A, B, C & D scales, but many later models added a reciprocal scale (CI), a cube scale (K), and on the slide reverse, T, L & S scales. This sample is a K&E 40533 Mannheim rule. CLICK HERE TO SEE A CLOSE UP SIMPLEX SCALE EXAMPLE. (use your browser RETURN to come back)
Duplex Slide Rules, which have a doublesided cursor and operate on both surfaces, with sliding and stationary scales. They are hand held to operate. This style rule usually has reciprocal scales (CI & DI), as well as folded scales CF & DF, generally at "pi". More complex ones add Log scales of various sorts, more trig scales, and sometimes special purpose scales like Sq1 and Sq2 expanded square scales.
and Circular Slide Rules, with stationary scales routed on a circular surface (to give greater effective scale length without poking into the workspace of the adjoining desk), and using dual movable cursors, or sometimes another rotating disk and a single cursor. Variations of this design may be anchored to a flat back piece (with rotating circular scales), or may have secondary rear functions. These can be either simplex or duplex rules in terms of overall design.
function is usually relative to C or D
Thanks to Craig Kielhofer for assistance in creating the trig scale entries. Special Scale Marks
What You Can And Can't Do With A Slide rule: Slide rules are based on logarithmic distance relationships, and can multiply, divide, take roots and powers, calculate logs and a wide variety of trig functions. They cannot add or subtract, and they require the user to keep track of the decimal point/order of magnitude in his or her head. They are very good for quickly solving complex formulas, especially those with many multiplied or divided terms, and visually reveal ranges of answers in a way that calculators cannot do. The essential accuracy of a slide rule is generally three significant figures over a very wide dynamic range. This accuracy is more than adequate for many engineering decisions and calculations, but it is not ideal for computing moon shots. It is worth mentioning however, that many bridges, buildings, basic and advanced electronic designs, and space ballistics work was done with nothing more advanced than an ordinary 10" slide rule. IN FACT, there is some rocket science here, as Pickett rules were carried (and presumably used) on three Apollo Space Missions, a fact that was loudly advertised on some Pickett boxes. We will assume they were not used to swat space flies, and had some real merit, as every payload ounce was very precious. You could calculate exactly how precious, if you had one.
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