Circular slide rules also were popular advertising gifts, often used as promotional freebies, says Schiller. "Even though they were the earliest form of slide rule, circular slide rules really didn't ...

Concise has specialized in circular slide rules, particularly for promotional distribution by other companies, since its founding in 1949. The company operated under the name Concise Co., Ltd., which ...

Object Details maker Pickett & Eckel, Incorporated Description This yellow aluminum circular slide rule has three clear plastic indicators, one blank. The other indicator on the front is marked in red ...

Two 10-inch log-log slide rules, circa 1965. This set up shows 12 x 12 = 144 under the hairline on scale D. This small circular slide rule would fit in a shirt pocket. It included an insert with ...

Every watch includes a 3 inch (8 cm) circular steel slide rule. To ensure you can make the best use of both slide rules, we’re including instructions.

So you could have 3 mean 0.03, 300, or — of course — 3. Of course, you don’t need to build the wheel with a rubber band — you could just mark the wheel like a regular circular slide rule.

But, as slide rule collector Eric Marcotte points out on his dizzyingly thorough website, it took a considerable length of time to get from these early prototypes to the modern slide rule, which ...

The big circular slide rule they’re shipping with the watch is a great conversation piece for your desk and, if you’re an engineer or someone who wants to get their smartypants on at the ...

So you could have 3 mean 0.03, 300, or — of course — 3. Of course, you don’t need to build the wheel with a rubber band — you could just mark the wheel like a regular circular slide rule.

Rectilinear and circular slide rules were the most popular shapes. In the U.S., the biggest manufacturer was Keuffel & Esser (K&E). The company produced its last slide rule in 1979, which it donated ...