Update on a '1655' project...

[automatico]

On 3-25-10 Stilty posted :

I will be converting a standard 1570 w/ date into a 1575 GMT movement in the near future. I have noticed from tech sheets that a 1575GMT is 6.47mm in height while the standard date model is 6.30mm in height. A difference of 0.17mm. I recall somewhere, that the date disc seat is taller on the GMT then regular movement in order for the date disc to clear the date driving wheel. The 0.17mm makes sense. Has anyone here converted a standard 1570 to 1575GMT?

Also, anyone have any issues with installing the GMT movement into either J&W, NDT, or Yuki? Are these cases made to gen 1575 GMT specs? Any issues with installing a GMT movement in the cases?

I have the 1570 w/ date and the following parts on the way:

#8038 - center second pinion 5.70mm

#8037 - Cannon Pinion 3.39mm

#8039 - hour wheel with double toothing 2.44mm

#8040 - 24hr wheel 1.41mm

#8035 - Calendar Wheel nut

#8036 - Date Jumper

#8006 - Yoke for cam

#8008 - spring for cam yoke

#8011 - stud for cam

#8030 - Center wheel with Cannon Pinion

I have #8034 Calendar Wheel in hand, so I think I'm covered as far as parts for the conversion, in fact a few may be redundant.

@Zig: Is #8035 Calendar Wheel Nut, the nut you are talking about? I also have #8011 Stud for Cam on the way. I believe this is the post you are talking about? I see 8034, 8035 and 8011 in a grouping on the Rolex sheets.

Zig posted:

-the calendar and GMT gears are going to be next to impossible to source, I have tried for years and haven't had any success, the only ones I have ever seen were on existing 1575 movements sent in for service. If you don't have those gears, the project is pretty much a no-go.

-the post for the calendar gear on the mainplate is almost certainly not long enough to allow you to install the new thicker GMT gear onto it. On a non GMT movement the threads just capture the nut, the new calendar gear is over twice as thick as the standard one, the post is not going to be long enough to allow the nut to be screwed down. This means you are going to have to remove, fabricate, and press in a new post, not an easy task and probably not many watchmakers who can do it.

- I would make a ring of brass the correct thickness to place between the mainplate and calendar ring and move the ring up as required (that is if the other issues can be solved). The dimensions are critical, because this will affect all sorts of other things, which I know you are well aware of...

Well...I read all this when it was posted but did not have enough sense to leave one of these projects alone. I am currently in a '1655' project using a NDT case/dial/hand kit, a 1575, some hard to find rolex GMT parts from Yachtmaster, and various $rolex$ parts from here and there.

What have I learned?

1...Zig was right.

Zig..."the calendar and GMT gears are going to be next to impossible to source, I have tried for years and haven't had any success, the only ones I have ever seen were on existing 1575 movements sent in for service."

2...NONE of the GMT parts are easy to find (in the USA anyway) and the calendar wheel p/n 8034 is very close to impossible to find. Stilty and I searched everywhere (Thanks for the help!) and finally found a new one at an obscure supply house in England. It was way over $100 by the time I got it.

3...The calendar spacer ring (7965) is harder to find than the 8034 and will usually set you back around $200 to $300 used. A new one will cost your right arm plus all your gold but I was lucky as one came with the parts from YM. You can probably shim the standard ring if you absolutely have to by carefully cutting a shim out of brass or steel shim stock. You can make one out of automotive valve adjustment feeler guage but it will probably have to be made in two pieces as feeler guage stock is usually not wide enough. I cut some out just to see how it went and when cutting it with very sharp scissors the edge will still curl up a little.

4...The NDT case is Ok and the 1575 GMT movement fits Ok.

5...The NDT case is extremely well made and very close to genuine.

6...Martyd3 was right too..."I tried to built the 1655 version of this watch. The project will set you crazy and you will end up broke. Why don't you find the best case available and buy a 2893 movement from FxrAndy? The end result won't be 100% accurate, but you will end up with a reliable watch and still have a couple of bucks in your pocket."

7...So far, I am about $3000 into this thing and it is not running yet. Stilty finished his and posted some pics September 6, 2010.

Looking back...I might spend the $$ for a high grade case but NOT for a genuine rolex GMT movement.

Edited May 25, 2011 by automatico

[lhooq]

Thanks for the update, R. It makes my current Valjoux 72 headaches seem very small in comparison!

[freddy333]

I converted a 1036 over to 1036GMT for my Phase II 6542 & if you think it is difficult/expensive to source parts for a 15xxGMT.......

As you surmised, the height difference is due to the slightly taller calendar ring. You MUST use the specified ring, otherwise, the date disc will come into contact with the underside of the dial & cause it to stick or bog-down during date changes. All in all, it took me nearly 2 years to source all of the parts for the 1036GMT conversion, many of which came from retired watchmakers I located through networking. Every time you pass a jewelry store, ask if they have an in-house or local watchmaker they can recommend. These are the types of guys who can be invaluable since they often have these hard-to-find Rolex parts sitting in the bottom of their spare parts box.

I know it has been said before, in the case of DW Daytonas & the like, but this level of construction is truly not for the faint-of-heart (or light of purse).

[automatico]

"I converted a 1036 over to 1036GMT for my Phase II 6542 & if you think it is difficult/expensive to source parts for a 15xxGMT......"

I am sure 1036GMT parts are a far worse headache than 1575GMT parts.

"As you surmised, the height difference is due to the slightly taller calendar ring. You MUST use the specified ring, otherwise, the date disc will come into contact with the underside of the dial & cause it to stick or bog-down during date changes."

Yes...this was Stilty's observation. I have worked on a few 1575GMT movements and am familiar with them but what I was NOT familiar with is the horrible parts situation. Parts for run-of-the-mill 1570/75 are bad enough today but since this latest parts gathering adventure, I figure GMT parts are probably not worth the trouble and expen$e to most F-stein builders.

Hopefully this short update will alert any potential 1575GMT/XII builders to the trouble that lies ahead. I just about have enough stuff to finish this project and rounded up a V72 for a DW Daytona project but am having doubts about a Daytona project now.

"All in all, it took me nearly 2 years to source all of the parts for the 1036GMT conversion, many of which came from retired watchmakers I located through networking. Every time you pass a jewelry store, ask if they have an in-house or local watchmaker they can recommend. These are the types of guys who can be invaluable since they often have these hard-to-find Rolex parts sitting in the bottom of their spare parts box.

I know it has been said before, in the case of DW Daytonas & the like, but this level of construction is truly not for the faint-of-heart (or light of purse)."

I know all the 'watch guys' in this area and none of them have anything.

This is not a 'rolex town'...it's a 'Timex town'.

[freddy333]

I know all the 'watch guys' in this area and none of them have anything.

This is not a 'rolex town'...it's a 'Timex town'.

Your best sources are older/retired watchmakers who work on everything, not the guys who specialize in Rolex.

The problem with older GMT parts is that, unlike other models, the GMT parts were not interchangeable with other non-GMT watches & Rolex generally only produced them for 20 or so years after production ceased. That leaves a tiny number of spare parts, which are rare & expensive in the hands of watchmakers who specialize in Rolex. To the older repair-anything guys, these parts are just old, commodity items. I cannot tell you how many times I heard 'Why do you want these old parts? No one uses them anymore. Why don't you just buy a new watch?'

This is why

(All gen except for the insert & repainted (gen) dial)

[gplracer]

So Freddy what is your process of finding these people? Do you go to jewelry shops in small towns and ask if they have any old watch parts for sale?

[freddy333]

I ask at every jewelry shop I pass in my normal travels. You are playing the odds -- the more you ask, the better your odds of finding what you need. Of course, you only get lucky once out of every 10-20 tries, but that is the way to find hens teeth.

[stilty]

Ughhh! Hearing your pain auto! Guess I got really lucky in my build!

ps. thanks for the great package I received in the mail!