sander Posted April 8, 2010 Report Share Posted April 8, 2010 The problem with the gen dial is that the date window is in the wrong position. It has the window about 1mm too much to the left. To make it work, you need a smaller date disk and the date window in the movement has to be moved to the left. Is this impossible??? Recently I did a project with a Lemania 283 movement. see here: http://www.rwgforum....-my-holy-grail/ This movement is build with a Dubois Depraz chrono module on top of a ETA 2892 movement. This means that the date disk for an ETA 2892 will fit a gen dial. Now the first question is, how to fit the smaller 2892 date disk into a 7750 movement???? First I removed the teeth and sanded the disk down from 0,35mm to 0,13mm. Than I took the 7750 disk and sanded it down from 0,48 to 0,35. After that I glued them together and the total high was 0,52mm (so I guess the glue is 0,04mm thick) So overall it's 0,04mm higher than the standard 7750 disk. This is not a problem. When you install the new disk, you will notice that it will rub the date jumper plate and the date indicator plate. I sanded them down, but unfortunately I sanded the date jumper plate a little too far. Because of this, the date jumper didn't work properly anymore. After I made a new plate, the date changed without any problems. After installing the extra gears to move the seconds to the 12 position, I noticed that the gap between these gears and the date disk, was big enough to have the disk freely move . So now the date is in the right position for the gen dial. After this I had to move the date window about 1mm to the left. The date window is attached to the plate which sits on top of the movement. I cut it off and enlarged the hole in the plate. After removing the window, I mounted the plate and noticed that everything worked as it should do. I also enlarged the date hole in the next plate (the one that holds the extra gears in place). So I ended up with a complete movement with a big hole instead of a date window. Now I needed to install the cut off date window into the big hole. For this I used the thin plate which is located right underneath de dial. I made the existing hole bigger and used some epoxy to glue the date window in the right position. After the glue dried, I sanded the plate and painted it black. When I positioned the plate with the window on the movement, it was perfect! Since I'm not having an extra gen APROO dial at the moment, I made one myself to see if it works. (I knew I was going to do this mod, so before I installed my gen dial in the above mentioned project, I copied it for the exact measurements) After the dial was finished and installed, I was thrilled to see that it worked. So yes it's possible to put a gen dial on a 7750 movement but it needs a lot of modding. Cheers, Sander Quote Link to comment Share on other sites More sharing options...
neverworn Posted April 8, 2010 Report Share Posted April 8, 2010 wwoooow awesome work sander! appreciate all that effort what you put in this mods! Quote Link to comment Share on other sites More sharing options...
Katerchen Posted April 8, 2010 Report Share Posted April 8, 2010 WOW!!! What an effort But seems like you did very well so far... Curious about what our watch (movement) moding experts will say about this issue. Respect! George Quote Link to comment Share on other sites More sharing options...
Katerchen Posted April 8, 2010 Report Share Posted April 8, 2010 @sander just curious: maybe stupid question but anyway, is the gap to the left with a gen AP ROO dial really as much as one entire mm or less? Quote Link to comment Share on other sites More sharing options...
FxrAndy Posted April 8, 2010 Report Share Posted April 8, 2010 Top work Sander Quote Link to comment Share on other sites More sharing options...
Rolexfinder Posted April 8, 2010 Report Share Posted April 8, 2010 Wow, you are the best Quote Link to comment Share on other sites More sharing options...
txcollector Posted April 8, 2010 Report Share Posted April 8, 2010 this is awesome Sander. I see this method as easier to do since the only additional part (apart from the dial) would be the DW. In the DD approach you need a new movement and some serious case mods. However this DW mod won't fix the crown position. Between the 2 methods (Dubois Depraz chrono module vs using the ETA 2892 on a modified 7750 based sec@12 donor, which one do you prefer? Quote Link to comment Share on other sites More sharing options...
1976 Posted April 8, 2010 Report Share Posted April 8, 2010 Excellent work Quote Link to comment Share on other sites More sharing options...
sander Posted April 8, 2010 Author Report Share Posted April 8, 2010 this is awesome Sander. I see this method as easier to do since the only additional part (apart from the dial) would be the DW. In the DD approach you need a new movement and some serious case mods. However this DW mod won't fix the crown position. Between the 2 methods (Dubois Depraz chrono module vs using the ETA 2892 on a modified 7750 based sec@12 donor, which one do you prefer? Well let me start to say that they are both not easy. The biggest problem with the DD module, was to find out how to use the chrono pushers because they don't line up. This took me hours and hours and hours and hours. Also If you don't have gen hands you have a challenge. The DD module needs a 0,90mm minute hand and 1,20mm hour hand. The rep comes with 1,20 minute hand and a 2,00 mm hour hands. Of course also all the chrono hands needs to be broached from 0,20mm to 0,25mm. I will try to write a post about it tomorrow. The mod with the 7750 movement was pretty much straight forward. It worked exactly as I planned. The only problem is that you have to work with really small margins. So it's really easy to screw it up. I found it also very frustrating to sand down the date disk to 0,13 mm. No power tools here, just some sandpaper. I think yhe most complicated part of mods like these, is to figure out what the best method is. Also you need a lot of spare parts and you shouldn't be affright to take some expensive risks Quote Link to comment Share on other sites More sharing options...
sander Posted April 8, 2010 Author Report Share Posted April 8, 2010 @sander just curious: maybe stupid question but anyway, is the gap to the left with a gen AP ROO dial really as much as one entire mm or less? It's less. I'm not really sure what the best way to measure it because all the dimensions are different. I made you a drawing so that you can take a look. The 7750 date disk is 1,3mm bigger than the 2892 disk (24,55mm -/- 23,25mm) If you defied that by 2 the difference is 0,65mm. Maybe this is the easiest way to tell? Quote Link to comment Share on other sites More sharing options...
Katerchen Posted April 8, 2010 Report Share Posted April 8, 2010 Again thanks for all insights and input on you project! Will definitely try to get you some gen hands as it worked out for kruzer... You deserve it George Quote Link to comment Share on other sites More sharing options...
sander Posted April 9, 2010 Author Report Share Posted April 9, 2010 Again thanks for all insights and input on you project! Will definitely try to get you some gen hands as it worked out for kruzer... You deserve it George Thanks mate! Quote Link to comment Share on other sites More sharing options...
cskent69 Posted April 11, 2010 Report Share Posted April 11, 2010 Found your other thread. Very ingenious! Quote Link to comment Share on other sites More sharing options...
HauteHippie Posted April 11, 2010 Report Share Posted April 11, 2010 Going to have to take a closer look and read this through once more. I'd more or less written off this model even though this it is one of my favorite gens of all. I had just not been interested in the 7750 version and didn't think what you've done was possible. Thanks for pioneering the way, but I have to admit you're making it sound a lot easier than it is.... making a new plate, sanding down datewheels and gluing them together keeping the alignment perfect... no easy tasks. Quote Link to comment Share on other sites More sharing options...
Jkay Posted April 11, 2010 Report Share Posted April 11, 2010 To answer the question you posed in your other thread ... your problem was the topic you chose. It asks a rather obscure question instead of proclaiming loudly that you've cracked an un-solvable problem. Your topic deceived members into ignoring your post. Congratulations to you, and thank you for putting a lot of work into solving a problem that no one knew could be solved. Quote Link to comment Share on other sites More sharing options...
aanival Posted April 11, 2010 Report Share Posted April 11, 2010 WOW,.. really amazing work here... Quote Link to comment Share on other sites More sharing options...
bosk Posted April 11, 2010 Report Share Posted April 11, 2010 seriously impressed! Are u a watch smith or is this just a hobby? Quote Link to comment Share on other sites More sharing options...
krpster Posted April 13, 2010 Report Share Posted April 13, 2010 Holy moley! That is amazing work right there! Im not an AP guy but I sure can appreciate ingenuity at it's finest. Well done! I am sure many will be able to take advantage of this kind of information although few will attempt I'd wager since it seems a significant amount of skill is required. Kudos! Now post some pics of the final product! I wanna see I wanna see! Quote Link to comment Share on other sites More sharing options...
gran Posted April 13, 2010 Report Share Posted April 13, 2010 smartest mod of the year looking forward to more all the best Gunnar Gran Quote Link to comment Share on other sites More sharing options...
dluddy Posted April 13, 2010 Report Share Posted April 13, 2010 Just getting to read this one Sander. Another terrific post and amazing work, as usual Quote Link to comment Share on other sites More sharing options...
sander Posted April 13, 2010 Author Report Share Posted April 13, 2010 Holy moley! That is amazing work right there! Im not an AP guy but I sure can appreciate ingenuity at it's finest. Well done! I am sure many will be able to take advantage of this kind of information although few will attempt I'd wager since it seems a significant amount of skill is required. Kudos! Now post some pics of the final product! I wanna see I wanna see! Here you go mate!: http://www.rwgforum.com/topic/115655-ultimate-modded-watch-finished/page__pid__822657__st__0&#entry822657 Quote Link to comment Share on other sites More sharing options...
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