1951 Model A 950B Railroad Watch

Hamilton made a variety of pocket watches back in the day.   In fact, during the first quarter of the last century, there were about two dozen different pocket watch movements.

However, by 1941, only two "railroad approved" pocket watches were still being produced... the 21 jewel 992B and the superior 23 jewel 950B.  Both movement grades were offered in different cases so collectors will look for both the type of movement as well as the case it's presented in.

The 950B is a striking design and looks as great as it runs.   It's very popular with railroad collectors and normally commands a healthy premium over a 992B model.

The 950B was introduced in 1941 and produced all the way through 1965.  One of the two case varieties available in 1951 was the Model A.

The Model A case came in 10K gold filled.  The other case available in 1951 was the Model No. 2 "Bar over Crown" case and that came in both solid gold or gold filled.

The 950B was a replacement for the original 23 jewel 950 that was produced for almost 40 years prior to 1941.  The major differences between the 950 and 950B are in the balance design, hairspring, cap jewels and the mainspring barrel... otherwise the two movements are very similar in appearance.

One of the details that makes the 950B such a high-end movement is the solid gold train wheels and rhodium plating on the main plate and bridges.

I've envied the 950B for a long time but they're very expensive and I don't tend to use pocket watches.  There are a lot of wrist watches out there that are just as tempting and I normally go for those before a pocket watch.  However, if you were going to only have one pocket watch, the 950B should be a top of the list.

As fate would have it, I came across a nice 950B and the price was right so I jumped on it.  As received, it was running but I could tell that it hadn't been serviced in a while.  The enamel dial has a couple of minor hairline cracks - that can dramatically impact the value of a watch but they don't bother me as much as other dial damage like chips or repairs do.

The 950B traditionally came with a heavy gothic dial and baton style hands, as mine does below.

There's a little bit of a haze to the damascened finish but, even with that, the movement looks bright and shiny.

The bezel unscrews to reveal the lever at 1:00.  You need to slide the lever out to the setting position (as shown) in order to set the time.  Being "lever set" was one of the requirements for getting railroad approved.

Once the two case screws are removed from the back, the movement comes right out the front.  Great care has to be taken to make sure I don't fat-finger the movement and drop it on the balance side - as that would break the balance staff.  Three dial foot screws secure the dial to the main plate.  Once they're loosened the dial will lift straight off, and take the second hand off with it.

Another sign that the movement hasn't been overhauled recently is the light coat of verdigris on the dial washer.  The green oxidation ring is caused by the two dissimilar metals of the washer and the dial touching for a long time.

Four small screws hold the ratchet wheel onto the barrel arbor.  The ratchet wheel has a jewel in the center to secure the barrel arbor.  In fact, both ends of the arbor rest in jewels.  Those are the two extra jewels that make this a 23 jewel grade instead of a 21 jewel movement.

When the smaller winding wheel is removed, you can see how it connects to the winding pinion that is under the barrel bridge (which has been removed).

Removing the two train bridges is as easy as unscrewing four screws.  The bridges just lift off to reveal the solid gold center wheel, 3rd wheel and 4th wheel.  The escape wheel is steel.

With the balance out of the way, all that is left to come out is the pallet fork, which is held in place by it's bridge.  You can see there is a cap jewel over the pallet fork's lower pivot.  Both pivots on the escape wheel, pallet fork and balance staff have cap jewels, top and bottom.

Pretty much everything has been taken off now and is ready to be cleaned.

A nice white alloy mainspring will give the watch plenty of run time.

All the parts have been cleaned, dried and are ready to be reassembled.  They are noticeably brighter than their "before" state.  Fresh oil will be applied to each of the bearing surfaces so the watch will run as close to friction-free as possible.

The running movement goes onto the timer.  A 16 size pocket watch movement is way bigger than the usual 6/0, 8/0 and 140/0 movements I typically work on... but the timer accommodates it just the same.

I took my photo before the timer was able to calculate the amplitude but the beat rate is a little slow and the beat error is on the high side of acceptable.

A little tweaking to the micro-regulator speeds up the watch slightly.  The amplitude is a vigorous 310 degrees.  The beat error could be reduced if I took the balance off and tweaked the hairspring collet the right direction but, to be honest, I'd be tempting fate and the benefit gained by a lower beat error is way less than the risk of potentially goofing up the hairspring.  It's not like I'm planning on running a railroad anytime soon.

With the dial and hands reinstalled and everything put back into the freshly polished case, this 1951 Model A 950B is a fine looking watch.  I may keep my eye out for a defect-free dial but otherwise this watch looks fantastic to my eye.

It's too bad I have to cover up the movement with a solid case back.  There's something very satisfying about looking at a running movement after having taken it fully apart, cleaned it and reassembled it.

1968 Thinline 6508

Hamilton merged / acquired a couple of Swiss manufactures in the 1960's... Huguenin and Buren.  The sleek looking H logo on 1960's watches is thanks to Huguenin, which also used that logo.  And Buren contributed the micro-rotor movements used in Thin-o-matics.  Buren also provided the super thin movements used in the Thinline models.

A good example of a classic Thinline is the 6508.  It was introduced in 1968 and produced for two years.

The Thinline models used a very similar numbering scheme as the automatic models.  The first digit of the model number denotes the case material... a 2 is solid 14K, 4 is gold filled, 5 is stainless steel and 6 is rolled gold plate.  In addition, when the second digit is a 5, the case back is stainless.

So you know that the 6508 has a 10K RGP bezel with a stainless steel back.  The bezel has a brushed finish and I'm sure it looked interesting when it was presented on it's matching bracelet.

Tucked inside the case is a Hamilton 637 movement.  This 17 jewel Buren-based grade is super-thin, as you will see in the photos below.  The crystal is a faceted design - and can be somewhat tricky to replace if you're looking for an exact match.

I've had my Thinline 6508 for a few years.  The dial lost it's lacquer finish so I sent it out to be refinished.  Now that it's back, I'll give the movement and overhaul.

I decided to get the dial refinished because I had lost most of the seconds cross-hairs when the lacquer pealed off.  By the way, you can see the Huguenin "H" logo I mentioned above.

My refinished dial turned out pretty good.  International Dial matched the H and Hamilton fonts perfectly but my cross hair seconds register appears to be just a smidge long.  C'est la vie - it could be a lot worse.  The black baton hands match the hour markers nicely - but that's a detail not shown in the catalog image.  They definitely look original though so I doubt they are later replacements.

The stainless steel back snaps on and off.

The 637 is a small movement - not the smallest I've seen but certainly small for a men's model.  In fact, the Thinline 6508 could be easily mistaken as a ladies watch today.

This photo is a little blurry thanks to a tight depth of field - but it gives you a good idea of why this movement when in the "thin line" models.

The 637 is a bare bones, no frill movement.  It's very straightforward and easy to put back together.  In the shot below, everything is cleaned and ready for reassembly.

The running watch movement goes onto the timer.

That's not too shabby - 5 seconds slow per day, good amplitude and a beat error less than 1ms.

A couple of minor tweaks gets the performance to be even better.  There's a lot of adjustability to the 637.  A lot of people view the Swiss grades as being inferior to Hamilton's US-made models but I have to admit that the Swiss grades are a lot easier to adjust and fine tune.

With the movement and dial back to looking and running great, everything goes back into the case.  This watch is ready for another 45 years of wrist time... albeit probably on a woman, as this watch is really too small for most men to wear.

1960 Boulton II

In 1940 Hamlton introduced the Boulton, one of the most prolific models of all time.  It was produced through 1952 and then again in in 1954 as the Boulton B.  That was a long run, but not the longest.  Others like the 1955 Trent had longer continuous runs.

However, in 1960, Hamilton introduced a redesigned version of the Boulton called the Boulton II.  It was produced for nice additional years.  That makes the Boulton design the longest running design.  In fact, you an still purchase a new, modern version of the watch today!

The Boulton II has a lot in common with the original Boulton.  First of all - they're virtually identical in size and shape.  The even use the same crystal.  Beyond that, the differences become significant.

The Boulton II came in a 10K yellow gold filled case as opposed to the 14K filled case in the original.  The style of 14K solid gold numerals on the Boulton II's silver dial is sans-serif where the original 18K gold numerals were a serif style.  The Boulton II has a simple cross hair register for the second hand as opposed to a more detailed seconds track from 20 years prior.

Of course, the biggest difference between the models is the Boulton II has the 22 jewel 770 movement tucked inside.  The original Boulton had a 19 jewel 982 movement and it received the replacement, the 753 when the Boulton-B was was introduced in 1954.

I recently picked up a Boulton II project watch.  It looked like it would be a "diamond in the rough" because of the beat up crystal.  Just changing out the crystal would be a dramatic improvement.

The front of Bouillon's tend to show little wear, so the best way to assess a Boulton is the back of the lugs.  It's not unusual to see the seams of the gold filled case but often you'll see the tips of the lugs worn down.  This watch's lugs look a little worn, but not bad.

The crown on this watch appears to have been a "stone crown" - but the stone fell out of the center.  I'll replace that with a proper crown during the overhaul.

The 770 is a fine movement.  It's basically and upgraded version of the 12/0 movements that were introduced in the early 1950s - the 17 jewel 752 and the 19 jewel 753/754.  The extra three jewels on the 22 jewel 770 are cap jewels - otherwise, the 770 shares most parts with the earlier grades.

Everything is disassembled, cleaned and dried before being reassembled. I've also got a new glass crystal to top off the restoration.

The running movement goes onto the timer to see how it's performing.  The results were pretty good but the beat rate was almost 4.0ms.  I hate having to adjust the beat error on watches with a fixed hair spring stud - as that's just tempting fate.  However, 4.0ms is a high enough beat error to make me take on the risk of screwing up the balance by removing it and adjusting the hairspring collet.

When I first put the watch back on the timer, I ws delighted to see the two lines so close together.  The closer they are, the lower the beat error... typically, that is.  In this case, the lines are actually very far apart, so far that they approach each other on the other side.  So the beat error is actually much worse - at 9.6ms.  That means I moved the hairspring in the wrong directions.

In order to adjust the beat error, you're attempting to move the hairspring stud, relative to the impulse jewel - and thus center the impulse jewel with the pallet fork so the balance will swing equally to both sides.  If it's not centered, the balance will swing further to one side than the other and the degree of difference is the beat error.

In the shot below, you can see the hairspring on the balance.  The silver ball on the outermost coil is the hairspring stud.  It's secured in the balance cock when the balance is installed.  In order to move the stud relative the balance, I need to rotate the hairspring at the inner-most coil by rotating the brass collet that holds the spring on the balance staff.

Well, I'm moving in the right direction.  The beat error is a reasonable 2.4ms.  Notice the distance between the two lines.   I'm going to press my luck and see if I can get it even better.

 Well, fourth time is the charm - I was able to reduce the beat error to 0.8ms.  To me, anything less than 1.0 is very acceptable.  The risks of tweaking it again to improve it far exceed the benefit to be gained.

Now that the movement is running well, I'll turn my attention to prepping the new glass crystal.  Glass crystals need to fit just right.  The don't "snap into place"... they are held in place with UV cement.  So I need to carefully sand all of the sides so that it will fit exactly into the contour of the bezel opening.

My light tent makes the dial look a little splotchy - I think that's actually just reflections from the dial, as I don't see the splotchiness in regular lighting.  You can definitely see what an improvement a new crystal brings.

A new Hamilton crown is a nice finishing touch over the previous stone-crown.

1968 Accumatic A-508

Hamilton was introducing new models all the way up until the final days of US production in 1969.  One of the models introduced in the the 1968 / 69 season was the Accumatic A-508.  It was produced for only these two years.

Well, after about 360 posts to the blog, I've gotten to be pretty good at guessing what sort of model an automatic is likely to be.  It looks like an Accumatic and the since it comes in a stainless steel case, it's likely to be a 500 series.  If it was gold filled it would be a 400 series, unless it had a stainless back, then it would be a 450 series.  Get it?

Of course, I would still need a reference to know that it's a 508 and not a 501, 2 or 3, etc.

Tucked below the white dial is a Swiss-made ETA-based Hamilton 689A... a 17 jewel automatic model.

My A-508 project watch came with it's original bracelet, made by Kreisler.  It wasn't running though.

The 689A is a frequently used movement in the Accumatic line.  The earlier models often used the 689 - which is very similar with some minor differences here and there.  This one has some wear to the rotor carrier (near the partially worn word "Unadjusted".  The case back has a rub mark too.  Close inspection while removing the dial revealed that one the dial foot screws was missing... I suspect the movement was slightly loose in the case.

I found the missing dial foot screw under the balance - which explains why the watch wasn't running. After completely disassembling everything and ultrasonically cleaning all the parts, everything is ready to be put back together.

The trickiest part of reassembling this style of movement is to get the center wheel, third wheel, fourth wheel and escape wheel all lined up at the same time so the train bridge will drop into place.  This is one of the unique situations where the "center wheel" isn't in the center at all.  It's actually off to the side.  The fourth wheel is in the center though - as it drives the second hand.

Now that all four wheels are installed, I can put the pallet fork in place.  Installing the wheels without the pallet fork allows me to see if the wheels will spin together - that means everything is lined up right.

In this shot, the movement is back to running condition, as shown by the blurred balance wheel.  The center wheel jewel is the one nearest the top of the photo... it's technically the furthest from the center, making it more of a second wheel than a center wheel.  The mainspring barrel is the "first" wheel", by the way.

Putting the running watch on the timer, it's running with a good beat rate but the beat error is a little high - especially since I can easily adjust it on this movement.

There... a beat error of 0.1ms is just about perfect.  The amplitude is a little low, but I didn't fully wind the movement yet.

A new crystal completes the restoration of this very attractive A-508.  With the original bracelet, it now looks and runs good as new.