Welcome to Vintage Instruments: Slide Rules and More

Hemmi 149A, new in box with the original 48 page manual and leather case. The most powerful Hemmi pocket rule, similar to the Post 1461, which was also made by Hemmi. White laminate on bamboo. The box and manual show some slight storage spotting, but everything is new.

Scales: L, K, A [B, TI, SI, C] D, LL0, LL/0
LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1

A wonderful pocket rule.

A very nice, small, pocket size circular slide rule, new in box, with case and manual. Heavy white plastic on a metal disk. 3 1/8 inch diameter.

Scales: K, A, D [C, CI, L]

A 4 1/4 inch diameter circular slide rule. A good working size. Complete with box, case, and instructions. White plastic on metal disk.

Scales: K, A, D [C, CI, EI]
L, DI, D, tan, tan, sin, tan, tan & sin

A profesional, 4 1/4 inch, circular slide rule, new in box with case and manual. Heavy white plastic. This SIC (Scientific Instruments Co.) 300-B slide rule was made by Concise.

Scales: LL3, LL2, D [C, S, T1, T2, ST]
K, A, D [C, CI, B, L]

I have several Otis King's Calculators, the famous pocket-sized spiral slide rule. They were made by Carbic Limited, London, England and were also sold under other names such as Geniac.

The rules are made of metal and are collapsable, being only 6 inches long completely closed. There are two basic models, Model K and Model L. Model K carries a logarithmic scale 66 inches long, from 1 to 10, carried in two sections, Scale 423 (upper) and Scale 414 (lower). Model L has an upper scale like the Model K's. Its lower scale is graduated from 0 to 1, in 2000 equal divisions of .0005 each. This is used in conjunction with the upper scale to give direct readings of the logarithm of any number, by means of which roots and powers are obtained.

Prices range from $150 - $300, depending on condition, case, box, instructions, etc. For further details, please request information using the Questions and Wants button at the top of this page, or click the Total Catalog button at the top of the page, go to the Slide Rules section, and Search for the term Otis. Sample pictures are below.

Pickett sold only this one bamboo slide rule, a great collector's item. White laminate on bamboo. The rule is new, in its original plastic sleeve. There is no case.

Scales: LL0-, L, K, A [B, Cos/S, SecT/ST, T/T, C] D, two square root scales, LL0+
LL1-,LL2-, LL3-, DF [CF, CIF, CI, C] D, LL3+, LL2+, LL1+

Many slide rule makers produced long, 20 inch versions of some of their models. While not as convenient to carry as the standard 10 inch rules, the longer rules offered greater accuracy.

I have many varieties of 20 inch slide rules, which make great collectables, gifts, or user rules. A few examples are shown below. If you are interested, please click on the Questions and Wants button at the top of the page and ask for details.