A Course in Wristwatch Repair The Gruen Horological Text and Technical Bulletins. Compiled by Mike Barnett, 105 pages, black and white illustrations.

The Gruen Horological Text was really a joy to read. As a young watchmaker who has been exposed mostly to modern repair techniques, I found it reassuring to know that fundamentals of watchmaking have not changed. That is, the concepts that I was taught were also being taught in 1948. Unlike the WOSTEP textbook The Theory of Horology, which is full of formulas and theory about how watches operate, the Gruen text is an instructional guide in servicing and repairing mechanical timepieces.

The text follows the order of instruction in a watchmaking course taught by the Gruen watch company at a school they operated on their campus. At the beginning it covers watchmaking tools, their use, and preparation along with the basics of micro-mechanics including filing, sawing, and turning.

In the first 78 pages everything is covered from the critical basics like fitting the dial and hands and cleaning and oiling to the more advanced techniques like positional and temperature adjustment. The text is full of well written descriptions, step by step procedures, and accompanying illustrations. Obviously, hands on practice and constructive feedback are also necessary when learning these techniques.

Additional topics covered include:

• Balance wheel staff replacement, truing, and poising
• Hairspring formation, manipulation, vibrating, poising, adjusting, and untangling
• Jewel replacement
• Mainspring handling
• Escapement theory and adjustment
• Gear train calculations as well as how to recognize and solve problems with depthing
• Balance staff and stem fabrication
• Isochronal Adjustment
• Tightening loose cannon pinions
• Fitting and adjustment of watch bands

In addition to the basic techniques critical to watch repair of all brands, the book includes technical bulletins from Gruen covering the specifics of several Gruen Autowind models for gents and ladies, calendar models, and stem interchangeability.

For the beginner watchmaker this book serves as an excellent guide for topics that should be covered in their study of watchmaking. However, some caution should be exercised. While 95% of what is taught is still considered to be good watchmaking, some of the techniques would not be considered good watchmaking by modern standards. These techniques could be applied in the repair of vintage timepieces where parts are no longer available, but should not be used on modern production calibers for which parts can be readily obtained.

For the young watchmaker with modern training this book serves to build confidence in the techniques taught in school, as well as to expose the watchmaker to other techniques that were perhaps not taught in school. In addition, the book covers some topics appropriate to older timepieces but sometimes overlooked in modern training like the replacement of bezel type jewels and the turning of a new jewel setting.

For the experienced watchmaker the book is a good review of the basic techniques and a resource for technical information specific to some Gruen calibers.

The Gruen Horological Text puts forth an excellent watchmaking course that, if followed by a diligent student who has access to an instructor or mentor to critique their work, could produce a well qualified watchmaker.

UPDATE: We have redirected all book links directly to the author’s web page. When you follow any of these links to gruenwrsitwatches.com and purchase the book, you are purchasing the book directly from the author and you help support Mr. Barnett in his endeavors. Watchmakingblog.com also gets a small commission. Please mention that you read the review here to show your support for the blog.

In addition, fans of Gruen wristwatches can find lots of valuable information and discussion at the author’s page gruenwristwatches.com

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