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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, November 23, 2014

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.


Saturday, November 22, 2014

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.


Sunday, November 16, 2014

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.