Thanks for visiting my vintage Hamilton watch blog. I like to restore US-made Hamilton wrist watches back to their original glory and share my experiences with other enthusiasts. Use the "Search" space below if you know what model you're looking for. Feel free to leave polite comments or questions in the spaces provided. Also check out my "watches for sale" on my Etsy site - the link is on the right, just below.

Sunday, August 6, 2017

1910 No. 900 Pocket Watch - Every One a Masterpiece

I know some collectors who focus purely on pocket watches.  In fact, for the first 25 years or so of Hamilton's existence pocket watches were pretty much all they made.  Wrist watches for men didn't come into fashion until WWI.

Personally I find pocket watches to be little on the boring side.  However, there are some very unique and scarce Hamilton pocket watch movements that make finding them a fun and interesting challenge.  In addition, there is something uniquely appealing about 100+ year old time pieces that still perform as well as they did when they were new.

Hamilton truly made excellent pocket watches.

Unlike other well known American brands like Elgin or Waltham, Hamilton did not make entry-level watches.  It takes 15 jewels to "fully jewel" a watch movement.  Many brands started their line up with 7 jewel grades.  Every Hamilton model made after 1900 had a minimum of 17 jewels.  The pre-1900 models with fewer than 17 jewels are extremely scarce and highly collectible.

When you look closely at the design details and accouterments of Hamilton's higher end watches you can understand why Hamilton marketed their brand with the tagline "Every One a Masterpiece".

In 1910 Hamilton introduced a dress pocket watch with 19 jewels... the model No 900.  It was their first 12 size model, although it was followed quickly by the No 920, 914 and 910.  Over the next several decades a variety of 12 size dress pocket watch movements would be produced but the 900 started them all.

Back in the day you typically went to a jeweler to pick out a pocket watch movement and then selected a case for the jeweler to install it in.   You could get a lower-end 17 jewel movement and install it in a solid 18K gold case or you could get a high-end 23 jewel movement installed in a base-metal / nickel-silver case (not that you would, if you could afford a 23 jewel grade you could probably afford a solid gold case too).

Eventually Hamilton evolved to selling pre-cased movements and the No. 900 was one of the early pre-cased models.  The No. 900 was marketed as the thinnest watch made in America at that time.  It's not a railroad watch or a "working man's watch".  It was the sort of a watch a man of distinction would wear in the vest pocket of his three-piece suit.  The grade 900 was produced into the early 1920's, ending with about 1923.

When you look closely at the catalog depiction a lot of very intriguing details are defined.  First, the movement has 19 jewels... 17 jewels are rubies set in solid gold chatons (settings) and the remaining two are sapphires used for the pallet fork.  The train wheels are solid gold, except for the steel escape wheel.  The escape wheel takes the beating from the pallet fork.  In fact, it's the collision between the pallet fork and the escape wheel you hear when you hear the watch ticking.  Using steel was a superior choice for this high-wear application.

The balance was adjusted to five positions, reflecting all of the positions the watch might find itself in while in your vest pocket or on a table.  The compensation balance allowed the watch to be accurate throughout a range of temperatures and the term "isochronism" meant that the balance would keep a consistent beat rate regardless of the force applied by the mainspring.  The double roller escapement provided extra protection from the watch over-banking due to an accidental bump.  Lastly, every No. 900 was pre-cased in either a solid 14K gold case or a gold filled case that were guaranteed forever.

I recently landed a grade 900 pocket watch, mainly because I didn't already have one on the blog.  However, I also got it because I am a sucker for the aesthetic design of these early movements.  To me, every one of these watches deserve a clear display back... they are just marvels to look at and appreciate.  

My project watch arrived in decent shape and my main concern was whether or not the stem sleeve inside the pendant would still be in good condition.  Most pendant-set pocket watches from this era are negative set, meaning the springs inside the movement constantly want to push the stem and crown out to the time-setting position.  The stem sleeve works in conjunction with the stem to keep the stem in the winding position until you overcome it by pulling the crown out to set the time.  If the sleeve is worn, the crown will pop out on it's own, thanks to the force of the springs inside the movement.  Stem sleeves are unique to the case design and replacing them can be a challenge.  Thankfully, this watch case is in excellent shape.

There are three hairline cracks in the porcelain dial.  It turns out they align with the dial foot screws and I suspect that the dial was damaged years ago by someone trying to remove the dial without loosening the dial foot screws.  Oh well, it happens.  I doubt I'll look this good when I'm 107 years old.

The case back is nicely engraved with three initials. The first letter is a W but I don't know what the other two are... maybe and L and an S?

The dust cover inside the case back is missing the Hamilton crest engraving.  That was an option at the time, as you can see in the catalog, and it left this area available for personalization or an engraved dedication.

This case does not say solid 14K gold and it doesn't say gold filled either.  Back in 1910 jewelry standards for gold filled didn't exist yet.  Cases often just had a warranty period and the longer the period the thicker the gold on a filled case.   So a 10 year case had less gold than a 15 year case, and a 20 year case had less than a 25 year case, etc.  This case was warranted to wear "permanently" so if its not solid gold it's pretty darn close to it.

Here's the money shot for the grade 900 and why I'd love to flip the movement around and display it through the crystal.  This is just a beautifully elegant design in my opinion and one reason why this movement, and those like it, always sell for good money.

Two case screws hold the movement to the inside of the case.  Once they are removed I can pull the crown out to the setting position and swing the movement out through the front of the case.

There are three dial foot screws on the side of the movement.  When they are loosened the dial can be lifted off.

In this shot of the main plate you can see the fairly simple design of the keyless works and the spring levers that make this a negative set movement.  Without the stem pushed in, the natural state of the movement is to be in the setting position.  When you push the stem in (and hold it in place with the stem sleeve), the spring levers are overcome and move the clutch wheel against the winding pinion and put the watch in the winding position.

You have to be very careful when the dial isn't installed.  The second hand bit extends out of the main plate and is easily snagged and bent if you're not careful.

The 900 is basically a 17 jewel movement with two extra jewels to support the motor barrel.  A motor barrel is an interesting design, as you'll see further in this disassembly.  The barrel has a fixed arbor that acts like an axle that rotates within jeweled settings on each end.

I'll remove the crown wheel first.  It has it's own bridge that is held in place with two screws.

I decided to flip the movement around and remove the balance, just to prevent it from damage in the event of a mishap.

With the balance (and pallet fork) removed, I can take off the crown wheel's bridge and reveal access to the parts below it.

Two screws hold the barrel bridge in place and the entire assembly can be slid out once the screws are removed.  Now you can see that the ratchet wheel (aka winding wheel) is actually held onto the barrel.  In watches without a motor barrel the ratchet wheel just comes lifts right off.  However, that's not the case in this watch.

First I can separate the outer part of the two-piece arbor from the mainspring and now you can see the axle that goes through the barrel bridge and is supported by the jewel in the center of the ratchet wheel.  The outer part of the arbor is threaded into the ratchet wheel and you need to unscrew it in order to remove the ratchet wheel from the barrel bridge.

In this shot you can see the ratchet wheel and arbor are unscrewed and separated.  The outer part of the arbor engages the innermost coil of the mainspring.  The outermost coil of the mainspring is attach to the barrel.  So when the ratchet wheel is turned, the arbor turns, and that mainspring is wound.  As the watch runs, the barrel turns and the mainspring unwinds.  That's basically how all mainsprings work but the two-piece design of the motor barrel enables much less friction.

With the cover off the barrel you can see the mainspring inside.  Notice the direction of the coils... I'll need to remember that when I put a fresh mainspring in.

Sure enough, the mainspring is a bit set, although it's not as bad as it could be.  I'll replace it anyway.

The center wheel and third wheel are supported by their own bridge, held on by two screws.

The fourth wheel has it's own bridge.

Lastly, the escape wheel also has it's own bridge.  You are starting to see why this watch is a masterpiece.  Every one of these parts is specifically made for this movement and each bridge is stamped with the serial number of the main plate.

Phew!  Everything is cleaned and ready for reassembly.  There are a lot of parts to this watch.

A fresh white alloy mainspring will give this watch 40+ hours of run time.

You get one chance to install the spring without having to wind it manually.  So I need to make sure I align the direction of the spring correctly before I push it out of it's retaining ring.  I don't want to have to remove it and re-wind it.  Pocket watch mainsprings can really pack a wallop.

If you're lucky (or good) you can get the tab of the spring to align with the slot in barrel without too much difficulty.

Now I can add some grease to the mainspring and close the barrel by reinstalling the cover.

I need to put the four train wheels in place before adding their bridges, as the fourth wheel bridge blocks access to the third wheel.

The train wheels are back in place.

There's a long strip of spring steel on the side of the barrel bridge that serves as the click and keeps the ratchet wheel from unwinding when you wind the watch.  In the shot below I am installing the screw that secures the spring in place.  The business end of the click is actually on the right side of the ratchet wheel as the spring extends under the wheel from left to right.

I wound the watch up a little bit and installed the balance.  The movement is brought back to life and is ticking away with good motion.

I have no complaints with this performance... pretty much right on the money.

Now to reinstall all of the parts on the dial-side of the main plate.

Voila!  This No. 900 looks and runs fantastic, almost as good as it did in 1910 when it was originally sold.  I know it's a 1910 model based on the serial number of the movement.  Too bad about the hairline cracks in the dial but thems is the breaks.

Here's a shot of the case back now that's it's been polished.  I still can't tell what the letters are though.  Any guesses?

The dust cover is almost as pretty as the rest of the watch.  Did I mention every one is a masterpiece?

Finally, here's the movement, sparkling away in all of it's brilliance.  Sure is a pretty watch, don't you think?


  1. Beautiful watch, can your dial it in a little tighter. Just kidding. After destroying a K 451 and breaking the lug on a Guardsman II I am getting gun shy. I have a Nordon that runs but winds endlessly. Mainspring you say. I have ordered a mainspring. This will be my first try at that. Do I need a winder? After killing two nice running watches should I just wait and read and learn more and let the poor Nordon run as is. I also got my first Hamilton pocket watch. A 974 with a Montgomery dial. It has BC Clark written on the dial which is clean and no cracks. Running well with the lever set. I will not mess with it. I see the 974 is a budget watch, but nice to me. Thanks for the entertaining posts.

    1. Installing a mainspring using just your fingers is doable but it's tricky and hard on your finger tips. Using a tool is the way to go.

      The cost of tuition for the "doityourself" school of watchmaking is not free. It includes countless hours of great frustration separated by moments of extreme satisfaction. You have to remember that professional watchmakers go to school for upwards of two years to learn the craft and master the tools needed for tackling most challenges. Then they benefit from the supervision and mentoring of more seasoned watchmakers.

      The 974 is a fine watch movement, it's just not "railroad grade" according to most people's definitions. It was approved for some smaller railroads / trolley systems. Being lever-set it's actually a 974L, which is also kind of cool and a little less common than the standard negative set 974.

    2. The 974 L says BC Clark above the second dial. I checked and BC Clark is an old jewelry store in I believe Oklahoma City. So I guess someone picked out the movement then case and dial. It is 14K gold filled I believe. I understand the lever movement was to prevent the watch from being bumped and changing the time. Since it is lever set I have been keeping it running. It has a screw type micro set regulator. After a couple of adjustments keeping good time with the "official clock" on the internet.
      Also my Khaki Field Mechanical was running 10-12 seconds fast daily. Even after the few month break in. Adjusted it and after three days one second fast. The satisfaction thing. Just like the holed second shot when I played golf! Followed by the triple bogey K-451.

  2. Also Dan if you could use the 451, case, movement and all I will gladly donate it to you for future use.

    1. I'll take any free parts you care to donate to the cause. Contact me through Etsy or my email (by clicking the "click here" link about my photo in the upper right.

  3. I think the initials are just WS.

  4. I bought one of these today. A pity I can't bring it to you. Tom is right - WS only 2 beginnings and 2 endings.