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Welcome To The Sphere Research Slide Rule Universe archives. Learn about the amazing world of paper and plastic film rules called slide and wheel charts!
  Sphere Research Corporation
3394 Sunnyside Rd.
West Kelowna, BC, Canada V1Z 2V4
Phone: +1 (250) 769-1834
FAX:+1 (250) 769-4106

A great source for test equipment, repairs, calibrations, useful metrology information, and of course, SLIDE RULES!

The Slide Rule Universe
Click to VISIT or RETURN


To go to
The Slide Rule Marketplace

The Wonderful World of Slide Charts, Wheel Charts and Perrygrafs
Datalizer slide and wheel charts, CLICK to visit them!

*Not all slide rules are formidable wood and plastic monsters. Some of the most useful and commonly used rules are inexpensive cardboard or thin plastic "purpose built" devices. One of the original, and largest makers of these specialized rules was Perrygraf, originally based in Maywood, Illinois. They were very ingenious at adapting basic slide rule concepts into product selectors, parameter analyzers, and dedicated calculators of all kinds. Perrygraf was sold in 1968 to Nashua Corporation, which moved the company operations to Los Angles, California, and to Puerto Rico. James E. Johnson, formerly of Perrygraf, didn't want to move in the new re-organization, and continued to make and design slide charts in his home. He also eventually took on the private customers of Perrygraf founder Oscar Perry after he passed away, and founded American Slide Chart in 1970. American Slide Chart was very successful, and eventually took over former competitor Perrygraf itself in 1988, making it the largest producer of this type of slide rule product, as well as pop-up 3D calendars. Founder James E. Johnson died in 1988 and the business is now run by his three sons, James D., David and Craig Johnson. Perrygraf and American Slide Chart ran and operated as individual companies, and often competed for the same customers, but ar enow one entity. Datalizer is another major slide chart/wheel chart player, also in Illinois (Addison), the state that seems to be the birthplace of most US activity in this area. Datalizer offers a unique capability in the form of a wide range of very useful commonly requested stock designs which can be bought in small quantity (as low as 100 pieces non-imprinted), either printed or non-imprinted with your company information.
Datalizer Stock Examples
Datalizer BMI calc, CLICK for bigger PIC!
Datalizer BMI Calculator, CLICK for bigger PIC!
Datalizer Planisphere, CLICK for bigger PIC!
Datalizer Planisphere,
CLICK for bigger PIC!
Datalizer Profit Calcs, CLICK for bigger PIC!
Datalizer Profit Calcs,
CLICK for bigger PIC!
Datalizer Drink and Drive, CLICK for bigger PIC!
Datalizer Profit Calcs,
CLICK for bigger PIC!

*Some of these rules started out being fairly primitive, but many are very sophisticated such as the Planisphere above, and extremely useful for specific problem solving. The electronics industry has been a big user of these devices as product promotions and component specifier guides. The examples shown at the bottom of the page are mainly from my own personal collection over the years, and give a good idea of what is possible with this technology. These devices are still made today, and are one of the very few slide rules still in production. Where applicable, both side of the rule are shown. Clicking on the THUMBNAIL will bring up a larger view.

*Notes: Sizes are given as the over-all size of the rule itself. CAUTION, the images while compressed JPEGs, are large in size to show the rule details, and may be slow loading from remote sites.

*YOU CAN STILL GET THESE! This type of rule, often called a "Slide Chart" (or Wheel Chart if it's circular), is still manufactured in large volume, and here's where to go and get them. Thanks to Craig Kielhofer and his excellent detective work, we can now give you this contact information on current manufacturers. They even have WEB SITES! just click on the company name below to go there.

You can still get Slide Charts,
Wheel Charts and custom Slide Rules Here:

Datalizer, CLICK to visit!
New Datalizer 501 Westgate Drive Addison, IL 60101-4524
Phone: (630) 543-6000 Phone: 011+1+630-543-6000 E-mail: info@datalizer.com

CLICK To Visit Datalizer Slide Charts!
CLICK to Visit Datalizer!

Email Judy Studenski at Datalizer for Information HERE.

CLICK to Visit American Slide Chart / Perrygraf
American Slide Chart Co.

Now the amalgamation of ASC and Perrygraf
25 W. 550 Geneva Road.
Carol Stream, IL 60187
Phone: (630) 665-3333 / (800) 323-4433
E-mail: amslide@americanslidechart.com

CLICK to Visit Blundell-Harling

Drawing Boards, Drawing Equipment, Slide Charts and Navigational Aids Tel: +44 (0) 1305 206000 Fax: +44 (0) 1305 760598 E-mail: sales@blundellharling.co.uk

CLICK to visit IWA
CLICK HERE to Visit IWA in 3 Languages, with virtual working rules!

IWA Incorporated
attention: Christopher E. Gabbert
819 Newberry Drive, Batavia
Il 60510 USA

Tel: +1 630 879 1900
Fax: +1 630 879 1966
E-mail: cg@iwa-slidecharts.com

Slide Rule Type Size,
Core Material
(Back to Return)
SEARS Duplex

Gray and Clear Plastic

Universal Metric Converter, length, area, volume, weight, temperature. Plus a basic C/D slide rule.
Greey Lightnin
Duplex 8"

White Cardboard

Volumetric calculator for all shapes.
Instrument Specialties
Duplex 8"

White Cardboard

Shielding calculations. Abosorbtion loss, plane wave loss. Electric/magnetic field reflection loss.
Duplex 8"

White Cardboard

Battery performance calculator, battery selector.
Philips Duplex 8"


Multiple metric converters, formulas. C/D Scale slide rule.
Vibrachoc Duplex 8"

White Cardboard

Deflection, g-forces, velocity, frequency. Extensive mechanical force calculations for vibration related issues. Cover contains operating manual.
Spectrum Control
Duplex 8"

White Cardboard

Voltage/dB/Watts conversions. Wave formats.
Simplex 8"

White Cardboard

VSWR, loss, reflected power calculations. Rulers on one side
Simplex 8"

White Cardboard

Temperature, pressure calculations. Conversion factors on one side.
Anitec Simplex Circular 5"

White Plastic

Image sizing calculator (photreduction/enlargement)
General Semiconductor
Duplex 8"

White Cardboard

Transient/impulse voltage calculations, device selector.
Kemet Duplex
Microfarad Manipulator

Clear/Tan Plastic

Capacitive reactance, ESR, ripple voltage, power calculations.

White Plastic

Calendar Date finder.

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