I collect slide rules. For those of you who don't remember a time before
inexpensive electronic calculators, slide rules are simple but devilishly
clever calculating devices. Capable of performing many types of computations,
including multiplication, division, logs, antilogs, powers, roots and
trigonometric functions, slide rules were once the constant companion
of working engineers and scientists.
Around 1973, Hewlett-Packard introduced a revolutionary product, the
HP-35 electronic slide rule calculator. For the first time, a small electronic
device was capable of doing all of the computations done by slide rules,
and then some. Although the HP-35 was rather expensive (around $400, which
might be a week's pay for a young engineer), it was only a matter of time
before the price of calculators dropped to the point that slide rules
were no longer competitive.
Here is a list of the slide rules currently in my collection. I have
only begun to scan them, and I'll be adding more pictures Real Soon Now.
|Concise (Sama & Etani)
| Sama & Etani seem to have specialized in circular
slide rules, usually sold under the Concise brand. Many of these
rules were made for companies who used them as promotional giveaways,
and so they were often imprinted with company names, logos and
Concise (SIC) 300B
| Dietzgen, like many other makers of drafting and
engineering instruments, also marketed a line of slide rules.
Although not quite as common as rules from K&E, Post or Pickett
(at least in the U.S.), Dietzgen's rules were of the highest
|| Dietzgen 1734
| One of the major European slide rule makers, Faber-Castell
offered a wide variety of rules in wood and plastic, including
the unusual addiator rules with combined a slide rule with a
mechanical adding machine.
| All the Gilson rules I've seen are variations
on the same design -- circular solid aluminum rules of the dual-cursor
type. Many of these rules included scales for fractional equivalents,
screw sizes and thread pitches, presumably suiting them for
use in mechanical trades.
|| Gilson Binary
| As the manufacturer of most of the Post rules,
Hemmi is the most familiar Asian slide rule maker to those of
us in the U.S. Hemmi also sold rules under its own name and
others (Hughes-Owens in Canada, for instance). Although the
firm also made quality plastic rules, Hemmi is best known for
its bamboo-core rules.
|| Hemmi 149A
Hemmi 257 Chemical Engineering
|Keuffel & Esser
| K&E, the late great maker of drafting and engineering
instruments, was probably the brand name most synonymous with
"slide rule" for generations of American engineers. K&E's wooden
rules were made of celluloid-laminated mahogany. Plastic (Xylonite
& Ivorite) rules were also made.
|| Keuffel & Esser 4080-5
Keuffel & Esser 4081-3
(2 of these)
Keuffel & Esser 4161-1
Keuffel & Esser 68-1100 Decilon
Keuffel & Esser 68-1210
| The Otis King Calculators are long-scale slide
rules in which the scale has been wrapped in a spiral around
a cylinder. These clever British rules pack a 66-inch scale
into a package not much longer than a pocket slide rule.
|| Otis King Model K
| Pickett rules are distinctive for their metal
construction, as opposed to the traditional wood or bamboo cores
used by most other makers. Pickett capitalized on the "hi-tech"
feel of its aluminum-body rules (some early models were magnesium)
through heavy marketing to schools and students. Although Pickett
rules lack the finesse of other top brands (in my humble opinion,
of course), they did produce some rules of considerable sophistication
and complexity. Pickett also made a number of inexpensive plastic
rules (which were still way nicer than Sterling rules),
and even one model executed in bamboo.
|| Pickett 140
Pickett N600-T (2 of these)
| Frederick Post Co. (later, Teledyne Post) slide
rules were by and large made by Hemmi, except during World War
II, for obvious reasons. Like all Hemmi rules, these were of
very high quality, constructed of a bamboo core overlaid with
plastic scales. Post also sold some all-plastic rules as well.
|| Post 1447
Post Versalog II 1460
(2 of these)
Post Pocket Versalog 1461
|Scientific Instruments Co.
| SIC appears to have been a brand name under which
number of different rules made by various manufacturers were
marketed; the Concise 300B listed
under Concise also bears the SIC brand. Both of the SIC
circular rules I own are of very good quality.
|| SIC 1610
| Without a doubt, Sterling Plastics made some of
the world's very worst slide rules. All-plastic construction,
with sticky slides, misaligned cursors and smudgy scales, Sterling
rules were nonetheless fascinating to me as a kid. Since they
sold for about a buck or two at the five-and-dime, they were
within my budget, too.
|| Sterling Mannheim Trig #689
Sterling Decimal Trig Log-Log
Other Calculating Instruments
Here's a few other calculating instruments in my collection:
||Dalton-Weems E6B Flight Computer
||Tasco Pocket Arithmometer
Slide Rule Links
- Slide Rule
- Sells used & mint-in-box slide rules. Great source of information.
- Dave's House
of Slide Rules
- This guy cracks me up. A wonderful collection of rules, and a lot
of good information.
- Kung's Slide Rule
- Some good links to other slide rule-related web pages
- Liam's Slide Rules
- A very nicely-done slide rule site by a fellow amateur radio operator