H. P. Friedrichs (AC7ZL) Homepage





My Books 

My Books

Marvelous Magnetic Machines

Building Electric Motor Models From Scrap


This is the place to go to find out about my latest book project, Marvelous Magnetic Machines. Scroll down for a  summary, for a table of contents, and for links to news, reviews, and a photo gallery of projects

About Marvelous Magnetic Machines

You're standing in front of an old card table in a driveway at a garage sale. On that  table is a one-quart aluminum saucepan, a votive candle holder, pieces of some office machinery, and a wooden awards plaque. What do you see there? If you did not answer "a six-cylinder radial electromagnetic attraction motor," then you need this book!

H.P. Friedrichs (author of the build-it-from-scratch cult-classics The Voice of the Crystal and Instruments of Amplification) returns this time to explore the principles behind the operation and construction of  five simple, yet impressive, model electric motors.

Aspiring mechanical model makers are often discouraged by their lack of access to machine tools, like mills, lathes, or drill presses. In Marvelous Magnetic Machines, Friedrichs demonstrates that with some basic knowledge, an open eye, and a sharp mind, one can use commonly available (and often discarded) parts and materials to engineer one's way around any lack of expensive machine tooling. In fact, every motor in this book was built from scrap, and can be assembled with hand tools.

By the time you've finished reading Marvelous Magnetic Machines, you'll know where to hunt for and find materials, and where to salvage suitable bearings. You'll know where useful solenoids can be extracted from scrap, and how to fabricate bobbins to wind your own. You'll learn how to time your motors, fashion a connecting rod, make a commutator from scratch, use a hall effect sensor to detect magnet position,  use a transistor as a switch, and much more. Model steam and Stirling engine builders will delight in the aesthetics of the motors produced with Friedrichs' techniques.

The out-of-the-box thinking implicit in Marvelous Magnetic Machines makes it  an essential addition to the library of any would-be inventor, garage tinkerer, or basement gizmo-builder. At the very least, you will never look at the contents of a garbage can the same way again.


Marvelous Magnetic Machines - Table Of Contents

Introduction * Safety * Magnetic Principles * The Peewee Motor * The Texas Motor * The Christmas Motor * The Little Twister * The Copper Queen * Parting Thoughts *Appendices


Follow this link to see what's new with Marvelous Magnetic Machines. This is also the place to go to view my progress log.

MMM On Youtube

Click on this link to view a short demonstration of the motors presented in this book.


Follow this link to read reviews of Marvelous Magnetic Machines.

Photo Gallery 1   Photo Gallery 2

Follow these links to view some images of the machinery described in Marvelous Magnetic Machines. Here, you'll find color photographs and some wonderful 3D images produced with FreeCAD.

Bonus: Kaden's Motor

Prior to the completion of Marvelous Magnetic Machines, I posted some images of another "marvelous" machine which, while not in the book, was constructed for my grandson using materials and techniques described in the book. Click here to enjoy some photos of that machine.


(Rev 10 - 04/22/2021