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Slide rule makers There are still some slide rules being made today - as far as I can tell only specialised ones. This makes sense as in many specialised applications the relationhips are not linear and, in some cases, non-logarithmic. This means that they cannot be solved using multi-function electronic calculators.
M. H. Mear & Company This company based in England makes almost thirty different specialised slide rules. In many cases the relationships represented by the special scales are ones which cannot easily be solved by calculators.

A summary of the catalogue can be found here.

The company's  contact details are:
M H Mear and Company Ltd.
Calculator Designers
Ramsden Mills, Britannia Road, Milnsbridge, Huddersfield, W. Yorkshire, England HD3 4QG

Telephone: 01484 648181   Fax: 01484 657098

Their web site is at: 

IWA, Stuttgart, Germany. This company makes a wide range of specialised slide charts and slide wheels. They cover the following areas:

Chemistry and Pharmaceuticals
Construction Industry
Construction of Machines and Equipment
Electrotechnical Uses
Heating and Ventilation Equipment
Heat-Treating and Welding Equipment
Metal Processing
Motor and Car Industry
Other Applications
   Pipes, Flanges, Screws
   Textiles and Textile Machinery
   Weight Data

The company's web site is available in English, German and French. The address for the English version is:

Calcoolator Co This slide chart enables calculations of pipe sizes for cooling systems in English or Metric units This appears to be the company's sole product. The site was copyrighted in 1999 but I don't know when the rule itself was developed.


Feild's Wheel Also known as Feild's Hydraulic Calculators for calculating the flow of pipes when flow is under gravity. Can be used when pipe is full or part-full, radii from 4 to 72 inches and slopes from 0.04 to 10.0 feet per hundred.