Stanley - Calculadora - 1950-1960

Vintage Fuller Calculator by Stanley, Model 1 Cylindrical Slide Rule, Mahogany Case, Mounting Bracket & Original Paperwork, 1960.

An impressive English Fuller cylindrical calculator by W. F. Stanley & Co. Ltd., dated 1960 by its serial marking 12528 / 60, complete with a mahogany case, mounting bracket, instruction booklet and accompanying supplier’s certificate.

This ingenious instrument applies the principles of a slide rule to a spiral logarithmic scale wrapped around a cylinder. Its 500-inch calculating scale provides the equivalent of more than 41 feet of scale length in a compact, portable form.

The calculator has a dark brown Bakelite handle and fittings, a phenolic cylinder, printed scales and metal index arms. The reference tables on the inner cylinder are consistent with the Fuller Model No. 1.

The wooden case provides fitted storage for the instrument and its support bracket. Labels remain inside the lid, adding to its period character.

Particularly interesting is the accompanying Townson & Mercer Ltd. document, addressed to “Pet. Lab 1 P.R.D., West Moors, Dorset”. It describes a Fuller cylindrical slide-rule calculator in a mahogany case and certifies that the goods comply with contract requirements.

Included:
• Stanley Fuller calculator, serial number 12528 / 60
• Mahogany storage case, approximately 46cm long
• Mounting bracket
• Fuller instruction booklet
• Accompanying Townson & Mercer supplier’s certificate

Condition: the printed scales remain clearly detailed, the barrels move and rotate smoothly. The case has marks, scratches and areas of finish wear. The instruction booklet and certificate remain clean. No cracks noted to the Bakelite handle.

Calculating accuracy has not been tested. Please examine the photographs carefully as part of the condition description.

A substantial and visually striking example of British calculating technology before the widespread adoption of electronic calculators, appealing to collectors of slide rules, engineering instruments and scientific history.

The Fuller Calculator, also known as Fuller’s cylindrical slide rule, was introduced in 1878 by the engineer George Fuller of Queen’s College, Belfast. It belongs to a class of precision calculating instruments that employ logarithmic scales to perform mathematical operations mechanically. Unlike conventional linear slide rules, the Fuller calculator uses a cylindrical body wrapped with a helical logarithmic scale making approximately fifty turns around the instrument. This extended scale greatly increased the effective length of the rule, allowing calculations to be carried out with a higher degree of numerical precision.

The instrument was primarily designed for multiplication and division, the standard functions of slide rules, but additional scales enabled calculations involving trigonometric and exponential relationships. Such capabilities made it suitable for engineers, surveyors, actuaries, and others requiring relatively accurate scientific computation in the late nineteenth and early twentieth centuries.

Manufactured chiefly by the London instrument maker W. F. Stanley, the Fuller calculator remained in production for many decades and continued in practical use well into the twentieth century. Its longevity reflects the continued relevance of slide-rule technology before the widespread adoption of electronic calculators. The instrument finally became obsolete in the early 1970s with the introduction of handheld scientific electronic calculators, which provided similar functions in a more compact form.