Navitimer date fix....?

[knmwt15000]

Hi Guys,

I'd like to open by saying what a great forum this is. Lots of info.

I've been reading around about the Navitimer replicas and in the reviews the prevalent issue appears to be the drop out of the date number. This is a big deal to some I'm sure.

I was wondering if anybody has taken a good look at this to see if it can be modified to be raised to a more appropriate position?

Are there any pictures of the modified 7750 with the dial removed? This would help clarify what the problem is and how a little modification might be possible.

thanks

[b16a2]

Unfortunately the date can't be raised because some of the gears run directly over the top of the datering.

[paulw]

The date at 4 can't be fixed. The gen uses a 7753 movement which is different to the 7750 format used in these reps.

It's an issue for me also and couldn't live with it so the only option is to chose a date at 3 model.

[knmwt15000]

Thanks for your quick responses. I have found this, since I noticed that other models in the 3,6,9 configuration apparently use a similar (same?), modification.

Thanks to Francisco we have these of the Omega seamaster:

These show the engine with the dial on, the dial off, the first plate off, and the second plate off.

After seeing these I'm quite optimistic that this issue can be resolved so the mechanism can be modified. These plates have cogs that overlap the date ring partially, but in no place, on any of the plate is the date ring completely overlapped. This means that a little reengineering may solve the issue.

Here are the steps of modification I can imagine taking place

1) tap second plate into bridge on engine so it attaches above the mechanism via the bridge rather than the edge.

2) tap the first plate into appropriate parts of the second plate so again it does not need to attach at the edges of engine

3) grind the edges of each of these plates as far as is suitable to keep fit of cogs (only exposure of a circular area covering the outer few milimeters of the date ring is needed

4) add a appropriate spacer and new plastic date ring which thus bridges the two plates

thoughts....

thanks

[Bibbs]

Would be interested to see what conclusions are made.

Edited May 7, 2009 by Bibbs

[trailboss]

I gather you allready know a bit about watches?

If you can pull that off you would have a line a mile long of folk wanting the mod done.

Col.

[Bibbs]

Just a quick Q.

Could you not cut the top plate into two rings. A centre ring (that keeps the cogs in place) and an outer ring.

Then the inned edge of the outer ring (and the outer edge of the inner ring) could be thinned for a date wheel sized recess.

Then there could be a gap between.

This gap would be over the current datewheel.

Then a few spacers, and another datewheel on top.

[knmwt15000]

Just a quick Q.

Could you not cut the top plate into two rings. A centre ring (that keeps the cogs in place) and an outer ring.

Then the inned edge of the outer ring (and the outer edge of the inner ring) could be thinned for a date wheel sized recess.

Then there could be a gap between.

This gap would be over the current datewheel.

Then a few spacers, and another datewheel on top.

Cheers for your comments Bibbs. You've pretty much the idea. Except you would need to do it to the second plate too; since there has to be a continuous gap around the engine for the date ring.

I gather you allready know a bit about watches?

If you can pull that off you would have a line a mile long of folk wanting the mod done.

Col.

cheers, lol

Erm, No. I just haz a clue that's all I'd bet that this can be pulled off.

[krpster]

I think what you are proposing will theoretically work....a "c" shaped date wheel that wraps around any overlapping gears and has an overall height that reaches the backside of the dial. Like this....

However I think the manufacture and modifications to the required parts will be so difficult that it probably isn't worth doing. Firstly the upper date wheel will have to be slightly thinner then the first plate to be able to clear the second plate gear train and also stay below the backside of the dial (not sure if they are normally that thin so you may have to make one). The first plate will have to be cut back far enough to accomidate the width of the date wheel since it will reside at the same level. Then the real trick.... in order to assemble/disassemble the movement the attachment of the two date wheels would need to be done so that you can actually get them appart. I suppose you could glue them as you built up the movement but you will never get it apart again....at least not without breaking it.

It would be fun to mess around with for sure. Let us know if you give it a shot.

[knmwt15000]

I think what you are proposing will theoretically work....a "c" shaped date wheel that wraps around any overlapping gears and has an overall height that reaches the backside of the dial. Like this....

However I think the manufacture and modifications to the required parts will be so difficult that it probably isn't worth doing. Firstly the upper date wheel will have to be slightly thinner then the first plate to be able to clear the second plate gear train and also stay below the backside of the dial (not sure if they are normally that thin so you may have to make one). The first plate will have to be cut back far enough to accomidate the width of the date wheel since it will reside at the same level. Then the real trick.... in order to assemble/disassemble the movement the attachment of the two date wheels would need to be done so that you can actually get them appart. I suppose you could glue them as you built up the movement but you will never get it apart again....at least not without breaking it.

It would be fun to mess around with for sure. Let us know if you give it a shot.

Glad to see that people can envisage what I'm talking about and don't think it is too ludicrous an idea. I wouldn't say that the difficulty in modification is such that it probably isn't worth doing (since I'd give my right nut to have any of the 3,6,9 replicas without the ridiculous recess)

p.s. can't see your image

What I need to know is where can I get hold of an engine to try this out. Can the Asian engines be purchased somewhere? Does anybody have a broken one of these that I could have/buy to make a prototype with?

Thanks

[Rolexman]

Tri-compax mod:

It's not my pic but I can't remember whom it belongs to?

[knmwt15000]

Tri-compax mod:

pic removed

It's not my pic but I can't remember whom it belongs to?

Nice find Rolexman!

Gee whiz. That thing is just about perfect for modifying. No need for cutting down anything just putting a thin lip on the existing date ring and bonding a new one above the gears.

Does anybody have any clues where this image is from?

[RWG Technical]

Theory is one thing, putting what your proposing into reality is another thing altogether. I would have to guess that you don't have any practical watchmaking experience.

Do you think you have started enough posts on this one topic ?

RG

[knmwt15000]

Theory is one thing, putting what your proposing into reality is another thing altogether. I would have to guess that you don't have any practical watchmaking experience.

Do you think you have started enough posts on this one topic ?

RG

Hi Watchdog. To be honest the more I probe it looks like this mod is fairly easy; based on what I've seen here and my engineering experience. I do some experience with watches. Lets try and be optimistic. THE main flaw with these watches is the deep recess of the date ring. Please try and be constructive.

Lol re posts. I figure that the best way to get appropriate responses is to ask questions in the appropriate forums. I may be new here but I'm not new to forums and I used to be one of those guys who lurks in one specialised area and wouldn't notice if somebody asked a question that I could answer if they posted it elsewhere. You should consider the internet fortunate that I'm keeping it to just this forum lol

thanks

p.s. looks like the image belongs to andreww

[knmwt15000]

http://www.auctiva.com/hostedimages/showim...,0&format=0

Greetz.

looks like it's actually from yodap

[Bibbs]

Cheers for your comments Bibbs. You've pretty much the idea. Except you would need to do it to the second plate too; since there has to be a continuous gap around the engine for the date ring.

Didn't realise there were two plates. In which case you could cut the first plate with a thin gap (for the spacers), and the top plate with a bigger gap (the same width as the datewheel) so the date wheel is recessed/flush with the top of the movement.

But yes, I can't see the issue apart from it being very small tollerances, and the pulling apart for later servicing. If the movement was the size of a dinner plate it'd be easy!

Good luck, I can't see any *major* issues apart from time.

(I'd mentioned doing this a few months back, and didn't get a reply)

Edited May 8, 2009 by Bibbs

[trailboss]

If you want to try this I can put you onto a dealer who can supply a bare A7750 MVT.

Col.

[knmwt15000]

Didn't realise there were two plates. In which case you could cut the first plate with a thin gap (for the spacers), and the top plate with a bigger gap (the same width as the datewheel) so the date wheel is recessed/flush with the top of the movement.

But yes, I can't see the issue apart from it being very small tollerances, and the pulling apart for later servicing. If the movement was the size of a dinner plate it'd be easy!

Good luck, I can't see any *major* issues apart from time.

(I'd mentioned doing this a few months back, and didn't get a reply)

Good deal Bibbs, I like your idea about recessing the first plate. This is the solution for the engine I pictured initially I'm sure. For the second engine, pictured by Rolexman (original from yodap) the job of modifying the plates is not needed. However, some support for the inner edge of the new date ring will likely be needed in the areas of the date window and the gears to prevent any inner edge dipping which may be visible in the date window and might interfere with the gears.

Last night I spotted your previous posts on the subject. Glad I'm not on my own with my thinking.

If you want to try this I can put you onto a dealer who can supply a bare A7750 MVT.

Col.

Thanks trailboss, do tell; that would be great

[knmwt15000]

FYI

Yes, the solution seems easy. A friend of mine, about two months ago, gave to me the idea, quite similar to yours.

I am working on that just now. However, you need to modify some things. If you do not have a watchmaker lathe it is a very time consuming and difficult task. Tolerances are very tight.

I will post the results soon.

Francisco.

[importr]

I and many others have reiterated this before:

IF the mod is successful, you will still be left with an inaccurate date font for the Breitling.

You can't use an ETA 7753 or a Breitling cal.23 datewheel, because it isn't the same size as the asian 7750 date wheel ( the swiss 7753/cal.23 date wheel is slightly wider). Unless, as you say, the top plate was machined with a recess to accomodate the bigger wheel.

So after all the hard work, you could still be left frustrated. Until someone comes up with the correct font...

[knmwt15000]

I and many others have reiterated this before:

IF the mod is successful, you will still be left with an inaccurate date font for the Breitling.

You can't use an ETA 7753 or a Breitling cal.23 datewheel, because it isn't the same size as the asian 7750 date wheel ( the swiss 7753/cal.23 date wheel is slightly wider). Unless, as you say, the top plate was machined with a recess to accomodate the bigger wheel.

So after all the hard work, you could still be left frustrated. Until someone comes up with the correct font...

Thanks for the note. I think a custom date ring made from scratch is the order of the day. Does anybody know what font Breitling actually use? I know they have the single digits oriented parallel to the tangent and the double digits perpendicular... If you can get hold of OEM datewheels from Breitling for the navitimer these probably could be modified and used. Can these be obtained?

[importr]

I very much doubt that you could find an OEM Breitling d/w on its own, mate.

I've never seen one for sale anywhere, ever. By that I mean ANY Breitling calibre.

Granted, some complete Breitling movements come up for sale from time to time.

If the mod was successful, someone would have to scan the OEM cal.23 d/w in order for it to be resized & replicated onto the new d/w.

As far as I see it, the factories in China are probably best equipped (and funded) to do this job. Whether they would bother to do it is another matter!

[knmwt15000]

I very much doubt that you could find an OEM Breitling d/w on its own, mate.

I've never seen one for sale anywhere, ever. By that I mean ANY Breitling calibre.

Granted, some complete Breitling movements come up for sale from time to time.

If the mod was successful, someone would have to scan the OEM cal.23 d/w in order for it to be resized & replicated onto the new d/w.

As far as I see it, the factories in China are probably best equipped (and funded) to do this job. Whether they would bother to do it is another matter!

Fill in the blanks

[knmwt15000]

I've started to make a custom date ring which closely resembles the Breitling original for the navitimer.

Obviously this is crap - I couldn't help but rush so I could show you this as the font needs changing anyway but it's proof of concept. The font I have used is the closest I could find and it is better than what the reps currently carry. Note the proper orientation for the single digits. The size is correct and the spacing is perfect.

Anybody have any idea what font I should try out?

[deltatahoe]

Anybody have any idea what font I should try out?

i may be mistaken, but i thought lello took on a breitling datewheel at some point in time....

deltatahoe