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Tuesday, July 16, 2019

1958 Automatic K-412

It's been a while since I've come across a new Automatic K-series model.  Someday I'll have to make a "most-wanted" list and identify the models that I haven't come across yet.

As fate would have it, I was recently contacted by someone who inherited his grandfather's watch and it serves as a great reminder that all Hamiltons are worthy of being restored, especially family pieces.

The model in question is the K-412.  It was introduced in 1958 and produced for only two years.  It was introduced in the waning years of the K-series and the start of the Accumatic line.  So it could be a fairly rare model.  There are no production records from this time period, unfortunately.

The Automatic K-412 came in a 10K yellow gold filled case and was outfitted with a white dial embossed with yellow markers and numerals.  It also has a pearled minute track with tiny golden dots at each minute position.  Tucked inside the case is a 17 jewel 661 movement.

Check out my project watch below... notice anything unusual?  Where should I start?  The good news is at least it ticks - ha ha!  It has a serious case of dial rash and I don't think I'll be able to do much to improve it.  I could send it out to be refinished but embossed dials with pearled dots are very hard to get done properly.  The figures always seem to come back soft, like they've been over polished.

The gold filled case back is unremarkable and it's loose so I can get it off easily.  These types of cases are very robustly built.

I don't know where the hands went but I can tell you definitively that the second hand is missing because there's no bit to attach it to.  The tip of the 4th wheel is very easy to break off if you're not careful.

The movement appears to be in good shape but it's very dirty.

Although the watch is ticking, that doesn't mean it keeps accurate time.  I rarely check a watch on the timer before I take I work on it... I just assume it's not going to be very good and I'm going to take it apart anyway.  However, just for fun, let's see how this watch is doing?

There is no clear pattern to the trace on the timer although it is moving upward on a steep angle.  According to the sound of the ticking, the timer thinks this watch is running just over 5 minutes fast per day.

I looked in my stash of donor movements and check out what I found!  It's a K-412 dial.  It's not perfect but it's way better than what I started with... plus it has hands.

Here's a picture of the movement's 4th wheel (right) along with a replacement on the left.  Notice the extra portion on the end, called the "bit".  This is what the second hand attaches too.

I think I know which dial I would choose, how about you?  Refinished dials are not a problem with Hamiltons, as long as they are done properly.  That said, a nice original dial is always preferable to a refinished dial.

Everything is ready to be reassembled with fresh lubricants.

The moment of truth has arrived.  The partially reassembled movement is now ticking away with a good motion.  Let's see what the timer thinks of it now.

Well that's much better!  Now it's just a minute fast per day and the amplitude is well over 200 degrees.  The beat error of 0.2ms is right on the money.

A quick adjustment to the regulator index and this watch is now running like it just left the Hamilton factory.

The reinstalled movement is noticeably brighter and shinier than what I started with.

A fresh 28.7mm high dome crystal is definitely called for on this project.  Something needs to keep the hands on, right?

My merciless light tent reveals a little extra tarnish or finish loss on the dial but it looks way better in person.

I also relumed the hands and the dial so it will glow in the dark, when charged first with light.

Here's a wrist shot in more flattering (and realistic) light.  This is a remarkable transformation and I'm sure the owner will be delighted to get his grandfather's watch back.  Now he can enjoy it with pride rather than let it rattle around in a drawer somewhere.


  1. Good to see you back posting Dan. Missed it.

    1. Thanks! I’ve been busy with a lot of other life priorities, and not too many new watch projects either. Double whammy.

  2. My grandfather's hobby was watches restoration, I am going to show him your blog, he will surely find a lot of interesting stuff here, thank you for posts.