The Internet Craftsmanship Museum Presents:

Kozo Hiraoka

Winner, Joe Martin Foundation Lifetime Achievement Award for 2005

Added to museum: 1/11/05

A master at not only building steam engines, but showing others how to do so as well

Kozo Hiraoka at the drawing board. He believes hand inked drawings have a warmth and personality that is not conveyed by drawings done in a computer drafting program. His drawings are an important part of conveying the message as to how his steam engines can be built by others, as drawings are a universal language. (Click on photo for larger image.)


Kozo Hiraoka came to our attention through his books, which have given him the reputation of being one of the key figures when it comes to building your own live steam locomotive. In building these models Mr. Hiraoka has had to master many different techniques of metalworking and engineering, not the least of which is the ability to successfully size down a massive prototype to create a model that not only faithfully represents the look of the real thing but also functions in the same manner despite the differences imposed by the physics of size. In addition, he has taken on the even more difficult task of documenting his work to show others how to do what he has done. This involves masterful ink mechanical drawings and clear technical writing. To make matters even more difficult, he chose to present his work in a language that in the beginning was foreign to him. We feel Mr. Hiraoka's accomplishments deserve special recognition both because of the enormity of the task he took on and the masterful level to which he has passed what he has learned on to others.

Career work on big machines includes 200-MPH railway

Kozo Hiraoka, born in 1937 in Hiroshima, Japan, started his working life as a mechanical engineer designing industrial boilers with Mitsubishi Heavy Industries, Ltd. With the rapid development of the chemical industry around the 1960s, the company expanded their business to include the field of engineering/constructing oil and petrochemical plants, and Kozo was involved in that work throughout his career. Each plant consisted of varieties of equipment and machinery. His job was the engineering and commissioning of oil and gas plants, mainly for the Middle East. At the time of Kozo’s retirement at 60 years old, his employers requested that he continue in his job to assist with several projects. Further, in 2002 he was involved in the “Taiwan Shinkansen Project,” a 200-mph railway exported to Formosa. Though Kozo was not familiar with high-speed railway technology, the project team persuaded him to join them by explaining that there were several tasks that could be managed by him. As of 2004, he is enjoying the engineering work of a “real railway” of the highest service speed in the world.

Love of model engineering goes back to his youth

Since he was a schoolboy, Kozo was attracted by models like those of airplanes and small gauge railroads. In the beginning of his thirties, he realized his dream to have a bench lathe with a 7-inch swing, and started to build live steam locomotives. These working models satisfied him in the knowledge that: (1) the model runs with steam on the same principle as the prototype; (2) he could fabricate all parts himself; and (3) the model could be run by riding on a passenger car.

The most important subject of model engineering may be “how close to make the construction and performance of the small model to the prototype’s.” Because of the “geometrical power effect,” the smaller the model, the more difficult its design will be. In a model in 1/10th scale, for example, its area reduces to 1/100th and the volume to 1/1000th, while air, steam and other physical properties remain the same regardless of the scale. From the balance between engineering challenge and running performance, Kozo chose 3/4" scale (1/16th), or 3-1/2" gauge locomotives.

Building different types of locomotives

Among the various types of steam locomotives, those that strongly impressed him were the geared engines: Shay, Heisler and Climax. They were invented in the US in an era when steam was the only big power available. These locomotives were designed for the requirements of only one particular service: to run on a steep and rough track. The engineers who designed these engines dedicated their efforts to achieve the required performance. As a result, each type of geared locomotive had a distinct personality. To build the working models of these engines, Kozo had several issues to overcome. For example, the Shay (See Photo 02 in section at bottom of page) had a crankshaft with ten different centerlines: three for the crankpins, six for the valve gear eccentrics, and one for the journals (Photo 03). He developed a method to machine the single-piece crankshaft out of bar stock (Photo 04).

The Heisler geared locomotive (Photo 05) is equipped with a unique V-type engine (Photo 06). Its rotational power is transmitted through the line shaft to the farthest front and rear axles via bevel gears, and in turn power is transferred to the other driving wheels via side rods. It can be said that the Heisler is a symmetrically balanced locomotive.

Another geared locomotive, the Climax (Photo 07), required five pairs of skew bevel gears (Photo 08) whose centerlines were offset from each other similarly to the hypoid gears used in present-day automobile driving mechanisms (Photos 09-1 and 09-2). Initially, it seemed impossible for an amateur to machine this type of gear. Through several years of study, Kozo succeeded in developing the calculation formulas based on the “theory of uniform height tooth bevel gear on a hyperboloid,” by which industrially true gear teeth can be machined with simple tools by amateurs (Photo 10). Kozo’s instructions included how to calculate the dimensions of the gears and tools, and how to machine/heat-treat the cutting tools, as well as how to machine the gears with a homemade index head on the lathe. As the tooth profiles were logical on the mechanical geometry, the machined skew bevel gears ran smoothly with an excellent tooth face contact pattern. No filing was required for adjustment. As far as the skew bevel gears were concerned, the working model of the Climax locomotive was equipped with those designed by a more advanced engineering practice than in the prototype.

Writing instructions so others could build his engines

In addition to building the working models, Kozo has enjoyed designing, photographing, and making drawings and instructions as a package. Establishing the instructions was a pleasurable way for him to share the joy of model engineering with others. His first book, Building the Shay, was published in 1977 by Village Press, Inc., followed by sister books Building the Heisler and Building the Climax. Each book covers instructions for all components of the engine. Some live steamers may be pleased with the instructions for fabricating a one-inch pressure gauge with a deadweight tester for its calibration, and others would be excited by the theory and calculation formulas of the skew bevel gears in the Climax book. The design and techniques presented in the books had been verified in a professional way, such as with strength calculation and fluid dynamics.

Learning English adds to the challenge

To publish these instructions through Live Steam magazine, Kozo had to teach himself to write in English. Though he had been familiar with technical specifications in his business, the books for live steamers required something different from them. They should keep arousing the readers’ interest throughout the book. After several trials, Kozo found that the most efficient practice was to make a comparison table showing his original sentences and those rewritten by the editor for publishing the article. After receiving each issue of the magazine, he made the table and learned by comparing every sentence.

Besides the text, the most efficient tool to transfer an idea to the readers is a drawing, an international language. The instructions were shown with dimetric drawings (a kind of 3D drawing) for easy understanding (Photo 14). Kozo drafted and inked all the drawings using pencil and ROTRING pens. Though he is familiar with CAD in his business, it has not been used in his hobby drawings because he thinks that high quality handmade drawings are warm and more attractive for readers.

After completing the three books for building the geared locomotives, Kozo’s next project was an instruction book for beginners. His work for this book was started by selecting the prototype. Through an extensive survey, the Pennsylvania A3 Switcher was chosen for the best balance between fabrication and performance. The book contains instructions as well as a guide to select and use every tool required for building this engine. By following the illustrated instructions, the beginner can learn the techniques for, and enjoy the great pleasure in, building the working model from scratch.

Kozo’s current project is the “New Shay” construction series running in Live Steam magazine as of 2004 (Photo 16). This series contains the results of almost all his achievements in making difficult tasks easy. The book, Building the New Shay was published in April, 2007 and is Kozo's latest publication.

To beginners, Kozo always says: “Think, and find a sure and easy way. The pro does his job in a way by which even the novice can do it – while the novice tries to do it in a way by which even the pro fails.”

Special Lifetime Achievement Award

Mr. Hiraoka is seen with one of his engines, his books and his award plaque. (Click photo for larger image.)

The Joe Martin Foundation is proud to present the 2005 "Lifetime Achievement Award" to Kozo Hiraoka for his contribution to model engineering through his books on small live steam locomotives. His excellent illustrations, clear photos and technical writing have helped many people enjoy the pleasure of building their own live steam locomotives. Mr. Hiraoka will be presented with an award plaque and an engraved medallion in March, 2005 in recognition of  his many years of work in this field.

Books by Kozo Hiraoka

The following books are available through Village Press. (Click on any cover photo to see a larger image.)

Building the Shay

Building The Heisler

Building The Climax

  The Pennsylvania A3 Switcher, The first project for the beginner

Building the New Shay (Latest book, published April, 2007!)

Here are several examples of Kozo Hiraoka's work:

(Click photos for larger images.)


Photo 02: The 3/4" scale Shay geared locomotive described in Mr. Hiraoka's first book

Photo 03: The single-piece crankshaft for the Shay


Photo 04: Crankshaft machining instructions--a typical page from the Shay book.


Photo 05: The 3/4" scale Heisler geared locomotive described in Mr. Hiraoka's second book.

Photo 06: The V-type engine of the Heisler

(Though photographed upside down, this angle shows the mechanism as it would be more normally seen.)

Photo 07: The 3/4" scale Climax geared locomotive described in Mr. Hiraoka's third book.

Photo 08: The driving mechanism of the Climax
Photo 09-1:     A pair of assembled skew bevel gears
Photo 09-2: A skew bevel gear and pinion

Photo 10: Steps for machining the skew bevel pinion

Photo 14: Typical instructions with dimetric drawings
Photo 16: General Assembly Drawing of the New Shay

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