Teardown + Service: Omega Bumper calibre 351

Another day, another bumper… This one was sent in for a service by Dom from Connecticut, who inherited it from his uncle.

The watch was manufactured in or before 1949, as the first service date scratched into the back is 5-5-49.

The poor thing has had it a bit rough of lately – the crystal has a hole, and the watch is pretty battered and bruised – but still ticking!

Not great, but what you would expect from a watch that’s had a bit of a hard time. I’m sure all is well inside, and a new mainspring, some cleaning and some Moebius oil love will set things right!

The watch back has some damage as well – as if someone took a sharp punch and stabbed the back with it. Not sure I want to know how that happened ๐Ÿ˜‰

Attempting a guess, I’d say either a child or an angry wife.

The case itself has quite a bit of damage as well – about 2/3 to the right lug, there are some deep scratches.

Same on the crown side. I also note that the glass bezel doesn’t quite fit and is loose. Now what has uncle Cappy been up to?

According to the back, no lack of watchmaker’s love here: 1949, 1959, 1972, 1975, 1981, 1983 … but that’s it. So the last service is 29 years ago. Well, not everyone likes to scratch watches, and I for one don’t do it. You get an invoice as proof of service, and I won’t damage your watch by scratching into the back if you pay it ๐Ÿ˜‰

First impression is good – no obvious damage, not too much dirt, a nice and tidy movement in a battered case.

Movement taken out of the case.

Odd marks on the bezel…

I align the hands and take them off.

Lovely dial – and considering the age of the watch, it’s in decent shape – especially considering the state the case is in.

With the dial taken off, the movement goes into the holder. Firstly, I take off the winder bridge, the hammer and the ratchet.

Now it’s time to let the main spring down – my other hand would of course be on the crown, but I got to take this photo somehow ๐Ÿ˜‰

Now I can take the balance cock and the balance out. All looking good.

The balance under the microscope with focus on the hairspring.

Pallet fork and bridge taken out.

Omega never disappoints – lovely detailing and finishes on the pallet fork. There is some dirt, but that will come off nicely with a bit of rodico.

Just the barrel bridge and centre wheel left to take out.

The main spring has seen better days – which explains the feeble amplitude.

Top plate cleared.

The escapement wheel – quite a bit of dirt, but in good shape.

All the wheels, pinions and pivots are in great shape. Just as you would expect from an over 60-years old Omega!

Now for the bottom plate …

… and done.

With the movement taken apart, I’m turning my attention to the odd punch marks on the watch back.

With the help ย of my trusted staking set, I ever so slightly counter-punch the marks. I have to be careful here, as punching too hard will stretch the material and introduce a wider counter-mark in the back.

This looks quite good, I only have one wider “crater” left of the serial number left.

This is as good as it gets – the case is gold filled, and not solid, so I can’t polish out the marks that are left. Looks a lot better, and, honestly, you shouldn’t try to punch holes into watch backs! ๐Ÿ™‚

This photo of the case shows a repair – the pendant tube must have been ripped out at one point and someone set it back into the case using some resin. Considering that this is a microscope image, the repair is okay – no prizes to be won with that, but it does the trick and holds the pendant tube in place.

That’s my work for today done, I’ve put all the parts that can take it into cleaning fluid and a rinse afterwards, and I’m ready for more action tomorrow.

I found a new main spring atย http://www.obsoletewatchandclockparts.com/, and I’ve also ordered a new crystal from my usual supplier. ยฃ11.90 for the main spring including postage, and ยฃ5.83 for the crystal (most of that unfortunately spent on postage). With a bit of luck, the parts will arrive in the mail tomorrow.

And they did … the story continues here.


2 thoughts on “Teardown + Service: Omega Bumper calibre 351

  1. Christian- Dom checking-in. Wow …this is better than watching my car go thru the carwash! Not quite sure what Uncle Cappy was doing with the back to create those punch marks. Glad you’re on this project.

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