One of the interesting nuances of a hobby is learning all the little sources of trivia available. For example, Hamilton often tweaked the design of movements so that not all examples of the same grade are 100% identical. On the other hand, sometimes slight changes did, in fact, result in a new grade. Then, on the third hand, those same changes when made to another movement, didn't result in a new grade. It can be very puzzling.
In 1962 Hamilton introduced a stainless steel model called the Seaman... one of dozens of Sea-related models. The Seaman was only produced for a single year.
Based on the catalog image, the Seaman is a fairly unremarkable model... dare I say it's even a little boring? It's a bit of a sleeper though, in that it has a very nice US-made movement tucked inside as well as some other details that are not visible in the artist's rendition.
The Seaman has a two piece stainless steel case so it opens from the back. The dial is actually textured with concentric rings so it has a pearlescent look about it. It's a very clean, no-frills design.
Tucked inside the case is Hamilton's last version of their 18 jewel sweep second workhorse - the 736 movement. The 736 is an enhancement of the 1955 735, which was an enhancement of the 748 introduced in 1948... more on that below.
Restoring Hamilton's is one of several passionate hobbies I have and now that it's Summer I'm pulled in a number of directions. As a result, I've been trying to only focus on models that I haven't seen yet and after detailing over 400 models, new examples are a little harder to come by. So when I saw a Seaman come up for sale I jumped on it. In fact, I've never seen another... does that make it rare?
As received, it was in worn condition and has obviously been well used. The Speidel bracelet that came with the watch is in decent shape but it's not original so I'll remove it and save it for another day.
The back of the watch is a pie-pan shape and unscrews to open the case and reveal the movement.
The 18 jewel 736 movement is held in place with a movement ring and a spring ring surrounds the movement ring to keep it all securely in place when the back is screwed on.
The inside of the case back is marked Hamilton W. Co Lancaster PA but the case itself was made in Switzerland. I've seen a number of Swiss-made cases from the early 1960's that housed US-made movements and suspect it was one of several cost-cutting initiatives that Hamilton had in an ever-challenging and evolving marketplace.
The lighting in my workshop makes it hard for my camera to reveal the texture of the dial. It's in great shape and I'd hate to try to get this dial redone so I'm going to leave it as is and not try to clean it up at all.
Unfortunately one of the dial feet is missing from the dial. It's actually in the movement. Reattaching a dial foot is possible but it's done by soldering - that could goof up the other side of the dial so I'll see if I can epoxy the dial foot on but that has a low success rate.
The 736 movement is different from the 735 movement in one way... it has a Glucydur balance. This style of balance uses a metal alloy that is robust to temperature variation and it is entirely smooth. There are no timing screws around it's perimeter like you'll see on the 735. The 735 departed from the basic 748 design by adding shock jewels to the balance - an enhancement that carried through to the 736. The spring-loaded cap jewels on the balance make it less likely to break a balance pivot by dropping the watch - but it's still possible, just less likely.
The first thing to come off the 736 once the mainspring tension is released is the train bridge. That allows access to the four wheels it supports. I can also take off the balance assembly, just to get it out of the way.
With the train bridge removed, I can remove the winding wheel and ratchet wheel. Then the barrel bridge can come off along with the center wheel and the mainspring barrel under the bridge.
Now just the pallet fork remains and two screws secure it in place.
While everything is being cleaned, I've polished the case and crystal. The crystal has a reflector ring and needs to be pressed back in place using a specialized tool. My usual round crystal tool - "the claw" won't work with a reflector-ring crystal. The tool below will push the crystal into the bezel - assuming I've lined it up correctly.
All the parts are now cleaned and dried so it's time for reassembly.
I find it's easier to put the pallet fork in first but you need to be very careful with this approach, as the escape wheel can move a pallet jewel if you're not very careful later on in the assembly process. The 748, 735 and 736 are by far the most challenging manual-winding movements in Hamilton's lineup when it comes to putting them back together.
Next up is the center wheel and mainspring barrel but first I need to reinstall the mainspring and give it a little grease.
The barrel cover aligns with a tab on the mainspring end to keep the barrel-end of the spring secure. The arbor end of the spring is able to move so you can wind the watch and store energy inside the barrel.
Apologies for the fuzzy photo - but here's a shot of the barrel and center wheel before the barrel bridge goes on and covers them both up.
Three screws hold the barrel bridge in place. Initially the 748 had a one-piece barrel bridge and if you needed to change the mainspring you needed to take the movement apart - what a pain! Hamilton got wise and changed the design two a two-piece style that allowed a watchmaker to access the mainspring barrel without taking the watch apart. Eventually white-alloy springs were introduced and breaking a mainspring was much less common so the barrel bridge was made a one-piece design again. This is a nuance you'll see if you look closely at 748, 735 and 736 watch movements.
The winding wheel is reinstalled with two tiny screws and then the ratchet wheel goes on with a single arbor screw. Now comes the hard part.
Getting all four wheels to line up at the same time requires great patience and a delicate touch. The 8/0 sized sweep second movements are unique in that they have a 5th wheel between the 4th wheel (for the second hand) and the escape wheel. How's that for a trivia point? It's very easy to break a pivot on the escape wheel or 4th wheel when reinstalling the train bridge - that's a classic newbie mistake that every hobbyist will learn the hard way.
Remember how I said I put the pallet fork in first and that I needed to be careful later on? Well, here's why... you need to gently poke and prod the wheels this way and that way, until you coax them into their respective positions. The escape wheel can easily move a pallet jewel out of place if you prod it a little too hard so great care has to be made when doing it this way. It's probably easier to reinstall the train bridge with the pallet fork not installed, but then installing the pallet fork later is a different challenge. To each their own, I prefer this way but would probably recommend installing the pallet fork after the train bridge if you don't have much experience with this movement.
Here's a good shot at the Glucydur balance wheel. The 22 jewel 770 movement also got this style of balance later on in the 1960's - but it didn't become a new movement grade... they kept the 770 nomenclature... go figure, another bit of trivia for you.
With the mainspring wound back up, the movement should come to life when the balance is reinstalled properly - and this one is running briskly so it's off to the timer.
It's running a bit slow but the beat error of 9.9ms is way too high. In fact, 9.9 is as high as my timer goes so it could be even worse. The two lines on the screen are close together, which is what you want to see but it's really because they are so far apart - if that makes sense. If not, you'll see in a moment what I mean.
Adjusting beat error is a white knuckle, beads of sweat on the forehead-type of activity. It is very easy to goof this up. I need to rotate the hairspring collet counterclockwise so the stud moves closer towards the center of the arc on the right side of the wheel. Right now it's at 4:00 and it needs to be closer to 3:00.
Them, once the hairspring is rotated, I need to reinstall the balance on the balance cock and get the hairspring into the two pins of the regulator fork. You can see in the photo below what it should look like.
Well, 5.7ms is better than 9.9 and the amplitude has come up above 200 but I really need to get it better than 5.7. I'll settle for under 3, as each attempt is a roll of the dice and I don't want to come up "snake eyes'. Notice how the lines are now separated from each other, they are actually getting closer together than when the beat error was 9.9. In the shot below, the line on top is on top and above the line on the bottom. In the photo three frames above, the line on the bottom was actually above the line on top - so it appeared like they were close together.
Okay... 1.1ms and the lines are much closer together. Now I just need to tweak the regulator and speed it up a little.
Notice how the two lines are now close together and approaching horizontal. The slight upward trend means its running a smidgen fast but that's purposeful. It will settle down eventually.
With the movement running properly, I'll flip it over and reinstall the parts on the dial-side of the mainplate... again, apologies for the slightly blurry photo.
I put a tiny dollop of rodico putty under the dial near the missing dial foot to help secure the dial in place. Then I reinstalled the hands and put it all back into the case. Now I just need to screw the back into the bezel and tighten it all back in place.
I was able to polish the crystal so it looks defect-free again. The watch looks much better than it did upon arrival and a nice teju-lizard strap completes the restoration. The watch now looks as good as it runs.
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.