stilty Posted March 25, 2010 Report Share Posted March 25, 2010 Hi Everyone, I'm looking into a new vintage project and have a few questions for the experts, past and current builders of 1575 GMT models. ie. the 1655 or 1675. 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? Did you encounter any issues with the date disc rubbing on the extra driving wheels? I'm wondering if my current date disc seat is too low, if I could shim it up so the date disc clears the wheels. Here is a picture of the standard 1570 w/ date. And here is a picture of the 1575GMT. Please note the extra driving wheel, and also how much higher the date disc is from the mainplate. 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? Any suggestions on who has the best 1655 case? I have been in conversation with Yuki, and he has informed me that their 1655 case may have issues fitting a genuine crystal, so I think their case is off my list. If I can't find a good 1655, I may opt for a 1675 project. Any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted March 25, 2010 Report Share Posted March 25, 2010 I can't offer any experience with the modifications needed to make the movement into a GMT one, I can offer thoughts on the following based on my experiences... - 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... - stay away from Yuki cases for this and any other projects where you are installing a gen rollie movement. Yucky cases are not properly made nor do they have the correct dimensions and tolerances to fit gen movements. NDT cases I have used have been good, J&W as well, also stay away from any and all of the modified rollie movements offered by these folks, they are garbage. - there are basterdized GMT movements available, where they use the minute wheel as the driving wheel for the GMT gear, stay far far away from these as well, they are total junk... Quote Link to comment Share on other sites More sharing options...
yachtmaster Posted March 25, 2010 Report Share Posted March 25, 2010 Stilty, do we have the the calendar and GMT gears that The Zigmeister is talking about? I was told by my watch guy that you can use the same ring but need a washer to raise it a little. Quote Link to comment Share on other sites More sharing options...
Martyd3 Posted March 25, 2010 Report Share Posted March 25, 2010 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 Quote Link to comment Share on other sites More sharing options...
stilty Posted March 25, 2010 Author Report Share Posted March 25, 2010 @Marty - 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. @yachtie - I figured shimming the date disc seat would be the way to go. The difference between the two movements is 0.17mm, so I figure that is the thickness of the shim I need. I wonder if I will need new screws as well? I guess I'll cross that bridge when I get to it. Quote Link to comment Share on other sites More sharing options...
Martyd3 Posted March 25, 2010 Report Share Posted March 25, 2010 Damn! I am not 100% sure, but I think you have all of the parts needed Quote Link to comment Share on other sites More sharing options...
stilty Posted March 25, 2010 Author Report Share Posted March 25, 2010 Why don't you find the best case available and buy a 2893 movement from FxrAndy? Are you working on this project? Let me know how it goes! Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted March 26, 2010 Report Share Posted March 26, 2010 It looks as if you have all the parts needed to do the modification, should be straight forward to get it done... Quote Link to comment Share on other sites More sharing options...
marc jacobs Posted March 26, 2010 Report Share Posted March 26, 2010 Last year I have a 1655 project with yuki. The watch case is perfect fit with gen 1570 movement. Dimension and tolerance is great. All parts to assemble smooth as well. Yuki also help me to conversion normal 1570 to GMT. Quote Link to comment Share on other sites More sharing options...
stilty Posted March 26, 2010 Author Report Share Posted March 26, 2010 Last year I have a 1655 project with yuki. The watch case is perfect fit with gen 1570 movement. Dimension and tolerance is great. All parts to assemble smooth as well. Yuki also help me to conversion normal 1570 to GMT. I was told by Yuki that a genuine crystal will not fit this case. Some problem with the bezel. I asked for more specifics, but was not given an answer. They told me if I want to use a genuine crystal, that I would need a genuine bezel. I found that the Yuki 1680 bezel retaining ID was too small to fit over the genuine 127. I had to sand it out until I was able to fit it over the crystal. I would consider going with a Yuki case if he was selling it for $200 or less, then I could justify finding another bezel. But when he is asking $550 for a case that only accepts his crystal... no chance. Have you tried to fit a genuine crystal to your case? Quote Link to comment Share on other sites More sharing options...
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