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Slide Rule
Specialty Slide Rules
About Slide Rules
Slide Rule History
Slide Rule Overview

Over more than 100 years, our company has utilized its experience and know-how to introduce more than 1,000 different types of specialty slide rules to people.
Besides slide rules used since a long time in engineering fields, such as mechanics, electricity, electronics, chemistry, architecture and civil engineering, these tools are also being used nowadays as measuring instruments for a wide range of application, including medical and health treatments.
The main advantage of slide rules is that they make possible to estimate the results of complicated technical calculations, investment compound interests or sales profit ratios through easy operation. They are particularly useful when these calculations have to be done frequently or repeated several times.
If you have already heard someone saying "If I had a slide rule...", try asking them why they are saying that.

Hemmi Slide Rule is selling the following specialty slide rules (plastic).
We will be pleased to hear and answer any enquiries in case you are wondering if we can provide slide rules that will meet your needs.
(However, we discontinued the sale and repair service of bamboo slide rules.)

"Weight control slide rule" (for health related calculations)

Determine the balance between body height and weight from "too thin" to "too fat".

It is mainly used for infants (Quetelet index) or in school for school-age children (Rohrer index). This slide rule can also be used by adults.
"Duct slide rule" (for ductwork and fluid design calculations)

In air-conditioning installation, if the air volume and another value are known among the unit pressure loss, air velocity inside the duct and duct size, the two other values can be calculated using this slide rule.
It is particularly useful in air-conditioning installation construction sites to calculate estimated values.
This slide rule is still being used in actual construction sites.

"Cardiothoracic ratio scale" (for medical calculations)

Calculates the cardiothoracic ratio (CTR) which shows the heart relative size seen in a chest radiograph.
A ingenious scale for measurement has been added to the slide rule's top to facilitate its utilization during medical practice.


We are currently manufacturing and selling the following specialty slide rules:

- Management calculation (management diagnosis, profit ratio)
- Pollution calculation (flue gas diffusion, etc.)
- Medical calculation (cardiothoracic ratio, lung function, infusion rate, etc.)
- Calculation related to health (BMI check, calorie calculation, etc.)
- Calculation related to aircrafts (load balance, etc.)
- Architectural design calculation (building structural design, etc.)
- Ductwork and fluid design calculation (air-conditioning system design, duct diameter, etc.)

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