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A late, eighteenth century, ivory scale rule by Dollond of London, which would originally have been part of a pocket set of drawing instruments. There are diagonal scales on the reverse. An early, nineteenth century, ivory, twelve inch scale rule by Cary. Unusually, the zero is not at the end of the scale, a feature of early rules. Two nineteenth century plotting scales, the upper in ivory, showing the upper face, and the lower, in boxwood, showing the diagonal scales on the reverse. These are both quality scales, this being indicated by the number of scales on the upper face and the fineness of the diagonal scales on the reverse. An eight inch, unsigned, triangular scale, and a twelve inch Stanley triangular scale. Both are boxwood and date from the early twentieth century. AJS No 7 twelve inch boxwood triangular scale rule.

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Founded in at Deansgate, Manchester by Alexander George Thornton, the firm grew to become one of the largest manufacturers of drawing instruments and slide rules in Britain. British Thornton is now a manufacturer of school furniture in Keighley. A traditional pattern set of electrum instruments by A G Thornton dating from the late nineteenth century. The instruments were purchased loose and I adapted an empty steel case to take them by making a set of velvet lined pockets to fit the instrument tray of the case in the same way as they would have originally been made.

A six inch circular protractor by Thornton of Manchester.

My collection of Sun Hemmi slide rules Sun Hemmi Slide Rules Hemmi was the largest manufacturer of slide rules, and is estimated to have sold some 15 million rules over its lifetime.

Sun Hemmi Slide Rules Hemmi was the largest manufacturer of slide rules, and is estimated to have sold some 15 million rules over its lifetime. These were sold under their own name Sun as well as redistributed for a large number of other companies, most notably the Frederick Post Co. Reflecting their Japanese origin, these rules were often made of bamboo with celluloid facings, which worked out very well since bamboo is naturally self-lubricating and withstands changes in temperature and humidity better than other types of wood.

Hemmi also made a number of plastic rules, which were generally of very high quality and compared well to other manufacturers. Given their extensive range of products, it is not surprising to see a number of specialized rules out there as well. Interestingly, Hemmi still exists today, but makes only hydraulic and related engineering components. According to Paul Ross and Ted Hume’s research project , by these rules reappeared with the label “Made in Occupied Japan” which was eventually dropped to “Made in Japan” around Also around this time, they started engraving 2-letter date codes on all their rules representing the year and month they were made.

The first letter corresponds to the year starting with B for and ending with Z in The second letter corresponds to the month, with A for January, B for February, etc. Although the date codes were prominently engraved and paint-filled in the early years, from the late ‘s onward they can be hard to spot as they are only lightly engraved in small letters, often near an edge. According to John Spivey’s research project on Hughes Owens, the switch from the old 17xx series nomenclature to the new xxx series took place between June and August Moreover, Hughes Owens also adopted the brand name Geotec for its slide rule and drafting products somewhere between June and May


Like the first automobiles that were produced, which were very expensive, the HP35 was like the “Winton” which was too expensive for the average worker or student. The other car makers still tried to keep their prices high, like HP, and a very small percentage of the populace could afford their autos. It was after that that the families who owned the slide rule companies stopped manufacturing them. TI must have learned from Henry Ford, who wanted to serve the people, rather than the board of directors.

oregon rule co. specializes in adhesive backed rule rs for oem manufacturing, industrial, commercial, security rule, security height rule, height rule, baby tapes, infant measuring tapes, infant tapes, consumer and retail custom applications. oregon rule has a complete line of protractors, metal rule s, dials, diameter calipers, angles, tape.

Introduction The teaching of mathematics to the engineering community is a subject that is very dear to my heart and something that must have been of considerable importance to the industrial nations. Two members of the senior professional teaching fraternity made considerable contributions to the subject.

Both men invented slide rules, one of which went on to become the final extremely popular standard scale layout for engineers, the Darmstadt standard. Whether Lord Kelvin actually thought of the slide rule we will never know, but Perry went on to design his slide rule. He reformed the teaching of mathematics in the basic schools 3 and instigated a very successful series of lectures for the working man, introducing them to mathematics 4. It is probable, but not proven, that he also mentioned the slide rule.

His greatest achievement was that he imparted the basics of mathematics to engineers at that time.

useful links about sliderules

Hemmi was granted Japanese patent in for laminated bamboo construction and success seems to have followed quickly thereafter. One can estimate dates of Hemmi slide rules from markings on the rules. I have not been able to narrow the date. Rules with model numbers date from before this changeover, rules with model numbers 20 and above were made after the changeover. Hemmi continued offering models 1, 5 and 8 to its distributors until WWII or later; these rules occasionally turn up with Post or Hughes-Owens model numbers but no Hemmi model number.

The Keuffel and Esser Co., also known as K & E, was a drafting instrument and supplies company founded in by two German immigrants, William J. D. Keuffel and Herman Esser. It was the first American company to specialize in these products.

A scale – x2 – The scale of squares on the body, The square of the D scale. To determine a square root, find the number on A and read the root on D. The process is reversed to find a square. Abacus – Calculating instrument that uses beads that slide along a series of wires or rods set in a frame to represent the decimal places. Probably of Babylonian origin, it is the ancestor of the modern digital calculator. Used by merchants in the Middle Ages throughout Europe and the Arabic world, it was gradually replaced by arithmetic based on Hindu-Arabic numerals.

The “Academy” title was used to denote models of slide rules intended for student use. The first Academy rules were the series, introduced at the same time as the and series Omega rules. Three separate strips were punched along with alignment holes, then machined using a vertical mill. Once fixtured together to maintain alignment, the strips were engraved and filled using filling paste supplied by Croda of Luton.

After lining up the components were taped together and end pieces cemented on the reverse side.

Greg’s Slide Rules

Stumbled on this looking for something completely unrelated: I have a few slide rules including a nice small Pickett N ES, the model chosen for the Apollo missions. A are real antiques if not classics. Mine is standard c which was marketed as a ‘beginners rule’; I used mine in middle school and early high school.

Oct 22,  · The flat disc slide rule works on the exact similar principal to that of the linear slide rule. If you can use a straight linear slide rule you should be able to use type. A further more accurate slide rule was the drum slide rule used by a lot of Drawing offices.

The second method uses a sliding linear L scale available on some models. Addition and subtraction are performed by sliding the cursor left for subtraction or right for addition then returning the slide to 0 to read the result. Standard linear rules[ change change source ] The length of the slide rule is quoted in terms of the nominal length of the scales. Models a couple of meters long were sold to be hung in classrooms for teaching purposes. Some high-end slide rules have magnifying cursors that make the markings easier to see.

Such cursors can effectively double the accuracy of readings, permitting a inch slide rule to serve as well as a inch. Various other conveniences have been developed.


Why did Hemmi start Versalog serial numbers with in ? In the Hemmi year code was ‘G’, the seventh letter of the alphabet. The tiny 1 mm high two-letter date code is moved from the top edge to the bottom edge, and is only stamped into the celluloid and not colored. It is sometimes quite faint, requiring magnification to find and read it. The COS scale is changed from navy to green; labeling is moved from the top to the bottom edge; Cat No.

Our notation for this rule is type 1b; prior rules are type 1a.

This book provides both an overview of the history of the slide rule, some of its cousins (e.g. circular and cylindrical) and its ancestors, and a reference table of practically all slide rules ever s: 2.

It seems that whoever is doing the tossing is saving the obviously good items. However, they do seem to occasionally make mistakes ie: I imagine they were a collector, because the range of of items is pretty wide and I doubt they all originated from the same person. They certainly had an interest in small baubles, doodads, and the like. Maybe they picked up these things at yard sales, or who knows, maybe they were a scavenger as well! I saved these items a few weeks ago.

As is usual for this spot I had to sort out a lot of junk to get to the good stuff. None of these items are particularly valuable, but they make great yard sale junk box material. The earring to its right looks to be gold and is stamped , which might be an old Portuguese gold mark.

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