WWII Model 23 Navigators Chronograph

You may have picked up by now that I have an affinity for Hamilton's military watches.  As a former US Navy officer, I guess you could say I view Hamilton's military models as a part of my heritage within "the long blue line".

One of the somewhat ubiquitous Hamilton military models is the Model 23 Chronograph.  It may be common, but it's certainly not inexpensive.  It's a 19 jewel, 16 size stop watch and was paired with the US Navy Model IV octant, as well as a couple of other sextants.  The Model IV octant was an aircraft sextant introduced in 1941.  You can see in this Sept 13, 1941 Life Magazine advertisement below that the Model 23 was clipped to the side of the Mark IV octant and a trigger pushed the button on the Model 23 to stop and start the stopwatch.

The Smithsonian National Museum of American History has a Mark IV Octant on it's website.  You can clearly see where the Model 23 Chronograph would have been installed on the side.

Navigators would use the octant to measure the position of sun or stars along with the time of day, etc. and calculate the position of the aircraft.

At any given time you can find a number of Model 23's for sale on eBay.  The trick, I'm sure, is to get one that is fully functional and in good shape, as getting replacement parts could be an expensive challenge.

I finally landed a Model 23 for a decent price (under $400).   It needed to be cleaned and serviced but was otherwise in good shape and functional.  The register at the 6 o'clock position is the second hand for the watch.  The large second hand is the stopwatch seconds and the register at 12 o'clock is the minutes for the stopwatch.  So this chronograph records up to 30 minutes.  When the stopwatch's second hand makes a full revolution, the minute hand indexes one mark.

You push the button on the pendant to start the watch or stop the watch and pushing it a third time will reset the hands to zero.

The case back of the Model 23 watches are engraved with the specific contract, etc. for which it was originally purchased.  This one appears to have been for the Air Force and the serial number on the movement appears to be post-1944 although dating these movements is tricky.  Most online tools based on serial numbers are inaccurate.   This case back also has what I assume was an air crewman's name.

Chronographs are quite complicated.  If you're looking forward to seeing me take this one apart, I'm sorry to disappoint you.  I don't have the confidence yet to tackle a chronograph so I sent it out to a pro to handle.

Chronographs have basically two levels.  What you see below is the chrono-level built on top of the regular watch works.  So you don't see the ratchet wheel for the mainspring, etc. that you would normally see on a 16 size pocket watch.  If you took the chrono-level off, you'd see the pocket watch underneath.

In this shot, looking over the balance and at the the third wheel, you can see it has an extra-long upper pivot with a wheel attached to it.  The bridge that says "Model 23" supports the pivot.

The extra wheel on the third wheel pivot is always turning when the watch is running.  It drives the little gold wheel to the upper left of it.  So the two wheels are always rotating.

When you engage the stop watch, the upper wheel moves over to the central sweep second wheel, as shown below.  Now the watch is powering the chronograph function.  As the sweep second wheel turns, it moves all of the other functions until the watch is stopped and reset.  Complicated, huh?

The Model 23 is really a pretty movement, in my opinion.  I've even seen these movements installed in a wrist watch case.  A 16 Size makes a very large wrist watch but if that gives new life to these extraordinary watches, so be it.  They deserve to be enjoyed.

For me, I'll keep this one in it's original form.

M is for Mystery

I recently learned that the M-series of watches were produced from 1961 through 1967.  It seemed like once I learned that I found a couple of new models.  Unfortunately I don't have the catalogs for the years other than 1964 so I can't really identify the watches.

One apparent common theme to the manual winding M-series with RGP cases I have found is they each have very similar case designs although they're not all the same size.

Compare for your self...  here's one from June 2014.

And this one from earlier in February this year.

Now I have another one.  As received it was in obvious need of a new crystal.  Sometimes crystals will craze like this over time if they are compressed too tightly during installation.

Although the physical sizes vary, the mystery models that I have come across all come in a one-piece 10K RGP case with very similar case designs elements... flat back, thin lugs, etc.

Without the crystal in the way, I can see that there is some glue residue around the outside of the dial from someone sloppily gluing the crystal on.

The dial design is very interesting.  It's got raised gold numerals and the inset hour markers are silver.  The chapter ring going around the perimeter is also silver.  This dial looks a lot like several models in the Electric Nautilus line from around 1963.

Behind the dial is a 17 jewel 688 movement.  I've seen these mystery models with 688 movements as well as 671 grades.

The case back is clearly marked Hamilton W. Co. Lancaster PA and the case maker is D&A.  That's been the case (pardon the pun) with the other models too.

Everything is cleaned and ready for reassembly.  I was able to get the glue off most of the dial except for on the chapter ring near the 2 marker.

I like the 686 movement - it's very easy to regulate once you get it running.

How's that for performance?

The dial and hand get installed and the movement goes back into the case.  You can still see some glue residue on the dial but that's the breaks, I'm afraid.  You can't be sloppy when it comes to watches.

The last thing to go on is a properly fitting 30.6mm high dome crystal.

A lizard strap completes the overhaul and you can clearly see what a huge difference a new crystal makes to a tired old watch.  The crystal hides most of the glue residue that was left on the dial.  This mystery model looks great to my eye.

A Tale of Two Watches

I recently picked up a project watch that I thought looked familiar.

It came in a one-piece rolled gold plated case.

When I went to identify it I thought it looked a lot like a 1964 Sea Haven.  But I was puzzled by the thinness of the bezel on my watch and the catalog says the Sea Haven has a stainless steel back.

Weird.

Then I remembered that I have a Sea Haven in my collection.  I rarely wear it because it has an expansion bracelet.  It looks exactly like the catalog (well, not the bracelet of course).  So something was up with my project watch.

Although the Sea Haven has a stainless steel back, it's still a one piece case and it cannot be separated from the RGP bezel.

Without the crystals in place you can see the dials are very similar.  They certainly have the same pattern but the finish on the Sea Haven is a radial finish while the other watch has a plain white finish.

The cases are both marked Hamilton Watch Co.  The Sea Haven on the left is quite different from the project watch.  The project watch is very similar to M-series watches I have seen though.  So I suspect the project watch is a post-1964 M-series watch... but I don't have any catalogs to confirm that hypothesis.

Both watches have the same size dials and both run a 17 jewel 686 movement.  Oddly enough, the project watch movement is a lot cleaner-looking than the Sea Haven.

The back of the project watch's dial has some numbers scratched in, specifically 1972... I wonder if the dial was refinished back then and lost it's original radial finish?

Both watches are completely disassembled, cleaned and dried before being reassembled with fresh lubrication.

The Sea Haven's movement is the first to be reassembled.  Next stop is the timer.

A little tweaking to the regulator brings the beat rate right in line.  The amplitude and the beat error look great too.

Now it's the project watch's turn to be reassembled.  This one is running nicely too.

This one started out running a little fast but a couple of tweaks slowed it back down.

I decided to put the expansion bracelet onto the project watch.  A new GS PHD crystal and a fresh crown complete the restoration.  It doesn't look too bad.

The Sea Haven gets a new black lizard strap.  With all things being equal, the original radial-finished dial makes the Sea Haven a much sharper looking watch.

1921 956 Pocket Watch

It's been a while since I've shown a pocket watch on the blog.  That's partly because I try not to repeat models and I've done quite a few pocket watches already.  You can find my past pocket watch projects in the menu on the right under "pages" or click pocket watches.

There are a lot of different pocket watch movements and I've really only done the more common ones.  Like a lot of collectors, my Hamilton mania began with a pocket watch that used to be my grandfather's... a 992B Railroad Special.

Speaking of common pocket watches, one particular model was introduced in 1914 for the "common working man", the 956.

Back in the first quarter of the last century most pocket watch movements were sold separately from cases. So you would go into your local jewelry store and pick out a movement and then pick a case for it to go into.  The 956 was the first 16 size pocket watch that was sold already cased.  It cost around $25 while the higher end pocket watch movements started at $28 or more.  With higher grade movements you had to buy a case too.  So the 956 was a "value-model".  Of course, $25 in 1920 was the equivalent of $300 today... so this was not an inexpensive watch.

Most railroads required a minimum of 21 jewels, among other attributes (open faced, lever set, etc.)  to gain railroad approval.  The 17 jewel 974 movement was approved by some smaller railroad and trolly lines so they're technically "railroad approved" in some respects too.  The 956 would not be considered a railroad watch... but most people didn't work on a railroad either.  Everyone still needed a reliable timekeeper though.

The 956 was made from about 1914 through 1924.

The story behind my 956 project watch is a bit complicated and a long one... but that's why my blog is called Hamilton Chronicles.

Believe it or not, I started out with an empty case.  It came with a parts movement that I used as a donor to complete another project a while ago.  I liked the case though, and specifically the train motif on the back.  So I decided to try to find a movement to put inside.

My case was set up for either a pendant-set movement or a lever set movement but I decided to go with a pendant set movement for the project.  I found a loose 956 on eBay for about $30 that didn't run and had a broken mainspring.  When it arrived I quickly realized it hadn't seen a watchmaker in many years - as it was filthy.  Based on the serial number, the movement dates to 1921.

My litmus test for determining the cleanliness of a watch is how bright the jewel settings are.  In this movement you can see the settings are dark brown - that's a sign of a dirty watch.  You'll be able see what they look like when they're cleaned later.

The enamel dial that came with the watch is cracked and chipped.  The hands that came with the watch are rusted.  There are some old plastic crystals that outgassed a chemical that rusted hands... that may have happened here or it may have just occurred from not having a crystal at all.  One thing is for sure, I'll need a new dial and hands.

With the dial out of the way you can see the the main plate is in decent shape.  This negative-set movement has springs to keep the watch in the setting position until the crown (and stem) is pushed in.  Pushing in the crown overcomes the springs and moves the clutch up and against the winding pinion so the watch can be wound.  When you pull the crown out, the springs move the clutch back down to the setting wheels - as shown below.

The first things off are the hour wheel, cannon pinion, minute wheel and the two setting wheels.

Now I'll flip the movement over and put it in my movement holder.  Since the mainspring is broken, there is no tension inside to release and I can just take it apart without worrying about breaking anything by the mainspring rapidly unwinding.

With the barrel bridge, train bridge and major wheels out of the way, I can remove the balance next.  I'll do that by first freeing the hairspring stud from the balance cock - as pointed out by my screw driver.  That will separate the balance from the balance cock.

Both balance pivots are in place, which is good - otherwise I would need to replace the balance staff.  The upper pivot (left) is a bit dirty.  You can see this is a single roller balance design.  The roller table is the disc-shaped part on the right that holds the pink impulse jewel.  Double rollers were used on the more expensive models and helped protect the balance from over banking if the watch was jarred accidentally.

Opening up the barrel allows me to see where the mainspring broke.  You can see the break occurred right at the start of the first coil.

The rest of the spring is "set" so I would have replaced this spring even if it wasn't broken.

All the parts are cleaned and dried.  I'll have to order a new mainspring but I happened to have an old one that I could use for now.

The first things back on are the escape wheel, fourth wheel and the pallet fork.  The escape wheel doesn't appear to be steel - that's another difference between the 956 and it's more expensive siblings.

With the escape wheel and fourth wheel covered by the train bridge, the next things to go on are the third wheel, center wheel and barrel assembly.

Before I put the barrel bridge back on I need to lubricate, reassemble and install the keyless works.  There are four parts; a rod that goes through the center, the clutch, the arbor and the winding pinion.

Here is the assembly ready to go back in place.

With the barrel bridge back in place I can wind the watch a little and get it ready for the balance to go back on.  If all goes well the watch will start running when I get the balance in place.

Success...  the movement is off to the timer.  Notice how clean and bright the jewel settings are now? You can tell this is a clean movement.

Well, the amplitude is a little low at 159 degrees.  That's probably due to using an old mainspring.  It will go up when I put in a new mainspring.  The beat rate of 15 seconds fast per day is okay but the beat error of 6.9ms need to be corrected.  I'll have to pull the balance assembly and rotate the hairspring to better center the impulse jewel in the pallet fork.

Ah... that's much better.  I like to see the beat error under 3ms and the closer to zero the better.

A new dial and better hands go on and the freshly overhauled movement gets installed into my railroad case.

Technically this is a bit of an oddball.  A 956 should probably be in it's original gold filled case to be totally proper.  However, this isn't a high end $900+ pocket watch so, who cares if it's not proper?

And here's a shot of the back... with the little train that started this entire journey.

To be totally candid, I went about this project the wrong way... starting with an empty case and finding a movement and all the necessary parts for it.  Starting from scratch like that is a costly proposition, especially when there are other parts to buy... like a dial, hands, crystal, crown and stem /sleeve like my watch needed.

When you buy a loose movement, you don't really know what issues you're going to face.  In fact, I recently purchased a loose 21 jewel 992 movement that was described as "dead accurate" by the seller.  He was half right - as it was dead and had a seriously broken lower balance jewel.  Fortunately I know how to fix such things.

My advice when buying a pocket watch is to get one with a nice case, nice dial and nice hands - then it's just a matter of getting it to run well.

Here's a shot of the finished project happily purring away inside it's new home.

UPDATE:

So I ordered a new white alloy mainspring...

Installing these large mainsprings is always a nail-biting experience.  They really pack a wallop if they unravel on you but I was able to slip it into the barrel on the first try.  I'll give the mainspring a  dollop of grease before I seal up the barrel

Well, it actually took a while for my timer to register the amplitude and a fresh mainspring yielded another 20 degrees of swing.  Normally I like to see the amplitude be north of 200 degrees.  I suppose I could use a lighter oil on the balance pivots but to be honest, this watch runs 40+ hours accurately on a full wind.  So what's there to complain about?