Advice request- removal of bezel and tachymeter ring Seiko 7T94 0BS0

[JamesRoss]

Hi

I've just acquired a Seiko 7T94 0BS0 Quartz Chronograph for clean up and restoration. It is scratched and filthy but otherwise fully functional.

It has a black coated bezel into which the crystal is embedded. There is a tachymeter chapter ring under the crystal sandwiched between the crystal and the body of the watch.

I assumed I'd be able to prise off the bezel to release the chapter ring to allow me to clean and polish the case.

The I can't seem to remove the bezel.. but the chapter ring is slightly loose. I'm uncertain if that is how it was when I received the watch. I think it's held in place by the movement.

If that bezel is removable I'd like to get it off so I can thoroughly clean and polish the case... and touch up or re-coat the bezel.

I'm at a bit of a loss. I can't see a way of pushing it out from the inside as the channels for the pushers and stem intrude into the watch body.

Photos below.

Thanks in advance.

James.

[jdm]

5 hours ago, JamesRoss said:

If that bezel is removable I'd like to get it off so I can thoroughly clean and polish the case... and touch up or re-coat the bezel.

I'm at a bit of a loss. I can't see a way of pushing it out from the inside as the channels for the pushers and stem intrude into the watch body.

Seiko fixed bezels can be removed, but in practice unless there is a compelling reason i think is better not to do that. You need a precise aluminum die with cuts to clear the tubes.

Good buffing and polishing work can be done with a small wheel, besides these are utility watches with some character and I think they deserve to carry some signs of their adventures as opposed to overpolishing.

[JamesRoss]

Hi JDM.

I thought as much. Thanks. I have already got the dremel at the ready....

Residual question is... how can I remove the crystal? The chapter ring impinges on the diameter of the crystal by around 4 millimetres all round. Will ot be OK to use a smaller diameter die?

I guess it doesn't matter too much if I break and have to replace the crystal....but looking at it the chapter ring is held in place by the bezel... hmm....

Thanks for your advice... very grateful.

Take care.

James.

[jdm]

11 hours ago, JamesRoss said:

I guess it doesn't matter too much if I break and have to replace the crystal....but looking at it the chapter ring is held in place by the bezel... hmm....

You must not press on the crystal neither on the chapter ring, only on the thin rim of the bezel that is exposed in the case. That is why the die must be precise. Once the bezel is removed the chapter ring will be free also.

[JamesRoss]

Thanks.

Confirmed what was thinking.

James

[xyzzy]

It'll be fine to press on the crystal a couple mm in with a slightly smaller die, unless it's already cracked.  If the chapter ring is metal, I've not had a problem pushing on it to press out the crystal.

You might need to remove the pushers, it depends on how big the inside of the bezel is.

The chapter ring might be trapped between the case and crystal, or between the case and bezel.  I.e., it may or may not come out with the crystal. I can't tell from the photo.  Bit blurry.

Getting the bezel back on straight can be a lot harder than getting it off.

[jdm]

28 minutes ago, xyzzy said:

It'll be fine to press on the crystal a couple mm in with a slightly smaller die

Correct, but what the OP intends to do is to remove the bezel for polishing. In that case the crystal can be left in place. 

 

28 minutes ago, xyzzy said:

You might need to remove the pushers, it depends on how big the inside of the bezel is.

Not only the pushers but their tubes and the crown tube also, as the OP had noted. Which is why the die should be cut instead, to avoid messing with these.

 

28 minutes ago, xyzzy said:

Getting the bezel back on straight can be a lot harder than getting it off.

Correct, and it may have a gasket which is easily pinched,  then one ends with a problem bigger than the initial. From that my initial advise, if ain't broke don't fix it. 

[JamesRoss]

Hi

Thanks all.

Sorted... and given a new lease of life... and a slightly new look with a nod to speedmaster mkii.

Thank you for your attention and help

James.

[xyzzy]

9 hours ago, jdm said:

Not only the pushers but their tubes and the crown tube also, as the OP had noted. Which is why the die should be cut instead, to avoid messing with these.

I've never had to do this to get a Seiko bezel off.  The pusher/crown tubes aren't that long.  On a large case, the pushers will just have long ends.  I think the long unsupported length past the tube makes them weak to bending.

On a small case, a 30mm die with a few grooves for the tubes will work.  If the bezel ID is greater than the diameter of the case inside, then the rehaut ring will be trapped by the bezel and one can press on that.

If I was going to polish the bezel, I'd want to remove the crystal.  One reason is to protect it.  But another is so I can grab the bezel with something on the inner diameter and spin it to polish.

[JamesRoss]

4 minutes ago, xyzzy said:

I've never had to do this to get a Seiko bezel off.  The pusher/crown tubes aren't that long.  On a large case, the pushers will just have long ends.  I think the long unsupported length past the tube makes them weak to bending.

On a small case, a 30mm die with a few grooves for the tubes will work.  If the bezel ID is greater than the diameter of the case inside, then the rehaut ring will be trapped by the bezel and one can press on that.

If I was going to polish the bezel, I'd want to remove the crystal.  One reason is to protect it.  But another is so I can grab the bezel with something on the inner diameter and spin it to polish.

You'll see from the photos I managed to muddle through. All part of the learning experience

Cheers

James.

[JamesRoss]

I took the crystal out and found this was the only thing holding the tachymeter ring in, behind a metal spacer. Once I stripped everything out of the case I gave up on trying to remove the bezel and just gave everything a really good clean. I took out the worst dents / scratches with careful sanding. Took the bezel back to bare metal (the pdm coating was horrible). 

I then polished the watch body, protected the polished surfaces with heat resistant tape and gave the bezel a brushed finish, sympathetically leaving evidence of the watch's previous hard life.

I polished the crystal using increasing grits of emery paper (dry, then wet) from 1000 to 10000 grit, finally a polish with glass polish.

I gave the back a brush finish.

I greased the o rings and seals.

Then patience and fun was to be had replacing the pushers (installing the C clips... ha ha) eventually I found the best technique involved constructing little rodico 'caves' to catch the little b***ers when they pinged off).

Chapter ring and crystal went back smoothly. I had to spend a bit of time straightening the battery terminals and the rear plate of the movement as the previous owner (presumably a gorilla) had changed the battery simply by ripping out the old one and shoving in a new one.

The whole exercise was simply a learning / confidence building exercise. I'm quite happy with the end result. There was a 50% chance of failure.

New leather strap on order which is probably more in keeping. I don't think even my meaty wrists will cope with a 22mm metal strap.

You may have missed the images.. here's the 'before and after".