this page contains links to articles I’ve written

A Day in Watch School

A Day in Watch School Part 1, 11/29/01

A Day in Watch School Part 2, 3/25/02

A Day in Watch School Part 3, 7/20/02

A Day in Watch School Part 4, 11/10/02

A Day in Watch School Part 5, 11/10/02

A Day in Watch School Part 6, 8/29/03

In-Depth Watch Reviews

The Best Years of Our Lives (IWC Cal. 89), with Terry Russell, 3/10/01

An Artifact of Innovation – The Hamilton/Buren Intramatic, 5/21/01

Ebel Lichine Sr with Lemania 8810 / Longines L.990, with Thomas Mao, 7/22/01

The Audemars Piguet Jules Audemars Handwind – Feat. the Cal. 3090 Movement, 1/15/02

The Seiko Diver’s 200 Meter SKX779 -Featuring the 7S26 Automatic Movement, 2/4/02

The Vacheron Constantin Malte “Grande Classique” – Feat. the Cal. 1400 Movement, 5/21/02

The Minerva Pythagore “Anniversary Dial” – Featuring the Calibre 48 Movement, 5/25/02

The Union Glashütte Julius Bergter Small-seconds – Welcome to the New School, 9/1/02

The A. Lange & Söhne 1815 – Homage to Tradition, 11/15/02

The Jaeger-LeCoultre Master Ultrathin, 2/18/03

The Patek Philippe Ref. 3919: A Star in Soft Focus, 6/19/03

The Girard Perregaux Vintage 1945 Large Date Moonphase – Bold and Modern, 9/23/03










5 thoughts on “articles”

  1. Hi again, and here’s a watch fixing update if you’re interested.

    Having been inspired by your excellent series, “Watch School”, I acquired some appropriate tools, and delved deep into my Grandpa’s antique 17 jewel Waltham. I successfully straightened and reconfigured the badly kinked overcoil hairspring, re-pinned the broken end into the stud, and modified the balance weights to compensate for the shorter spring. I took some photos of the process and added descriptive captions, and they can be found in the album, “Fixing my Antique Pocketwatch.”

    The watch is presently running very well.

    1. Hello Leonard,

      Congrats on getting your Grandpa’s watch running again. That is quite an accomplishment especially with the need to shorten the hairspring and form a new overcoil. Most very experienced watchmakers have never formed an overcoil, so the fact that it is running at all is impressive.

      It is worth mentioning that if you needed to alter the weights on the rim of the balance so drastically, then it likely means that the arms of the balance were out of true. In fact, in picture 15 it seems pretty clear that the arm is bent inward. Split bi-metallic balances are quite susceptible to deformation, so it’s always critical to carefully true them as much as possible before considering poising them.

      Also, a more refined way to remove mass from the balance screws is to remove the material from underneath the head, ideally in such a way that one cannot see that the screw has been altered. A lot of watchmakers over the years have come up with various poising shortcuts, but one must assume it is a lack of either training or dedication to craft that inspired many of these “innovations”. It is important to take into account the quality level of the movement you’re working on when deciding what is appropriate of course, but that looks like a pretty high grade movement and deserving of the best care one can muster.

      Lastly, when you alter the mass so significantly that far out on the arms of a split balance, you are drastically altering the temperature compensation and, if the arms are not true, introducing a temperature related poise error also (if it’s poised at room temperature then it will be out of poise at high and low temperatures). With the radical alterations you were forced to make to the hairspring (and the hairsprings other existing errors), it’s unlikely that temperature or poise errors are among the most prominent errors present, but something to keep in mind if you should dig into other temperature compensating timekeepers.

      Nice job on getting it running again and thanks for the pics!


      1. Hello John.

        You make good points, and they are duly noted. I’ll be interested to see how the watch behaves when the weather turns cold. I’m calibrating it in a pretty warm room right now.

        The watch already had some mangled screw heads and other cosmetic as well as functional damage when I first looked into it, and that partially accounts for why I allowed myself to be a bit bold in making alterations. I also thought it looked like one of the balance arms was out of true, but I felt out of my depth thinking about trying to bend the balance arms, with their unknown bimetallic stresses. For me, modifying the weights was a safer bet, and there’s always the option of reversing the changes at a later date.

        I’ve had the watch running for only a few days, and so it’s still a bit early to tell, but there seems to be about a minute difference between dial up and crown up. Surprisingly, it’s slower in dial up position, which I understand should be the reverse. When I had the watch open, I carefully studied the spring in motion, from every angle that I could manage, and it wasn’t rubbing or touching anywhere that I could see.

        Even though there’s always the risk that after I’m dead, someone will look into the watch and say, “What idiot did this?!”, it’s been a fun learning process (I have a bizarre sense of fun, obviously). But in the meantime, now I can’t make that joke anymore, about the watch being broken for 20 years, and STILL not running.


  2. Dear Mr. Davis,

    I came across your 6-part series about Watch School, on the Purist site, and I want want to let you know that I very much enjoyed it. The articles contain a wealth of technical information, great photos, and I really appreciated your good sense of humor as well.

    I’ve done a bit of amateur clock fixing, and I’m learning about watches now, with the help of articles like yours, and some careful hands-on experimenting. I read your piece about hairsprings, with suitable fear and trembling. I have an antique gold Waltham pocketwatch with a deranged hairspring (a Breguet overcoil, no less), and now I believe I have just enough knowledge to make me really dangerous.

    Thank you for your fine work.

    Leonard Solomon

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