A Solution to the Sunken DW of the Asian 7750

[Francisco]

Some gen watches employ an ETA 7753 movement. This movement is quite similar to ETA 7750, but the minute counter is at 3 position, whilst 7750 has the minute counter at 12.

As there is no rep of the 7753 movement, reps factories use a modification of the Asian 7750. This mod moves the minutes from 12 to 3. However, this mod produces a sunken Date Wheel (DW). Therefore, it is very easy to detect that the watch is a rep.

The objective of this tuto is to solve the problem of the sunken DW of modified Asian 7750, to move the minutes from 12 to 3, simulating a 7753.

First of all, let us check the final result, to clarify the objective.

Before the tuto:

After:

Let us find out why the DW is sunken and how we can solve it. Next picture shows better the sunken DW problem:

After removing the dial, the modification is visible. With 3 gears is possible to move the minutes from 12 to 3. However, the DW is below these gears, and that is the origin of the problem we want to solve.

The solution consists of placing another DW on the top of the gears, just at the same level as the DW is in the 7753, very close to the dial.

However, next picture shows the problem

[AmStaFF]

awesome, great tutorial Francisco

[Toadtorrent]

OMG...that is a brutal amount of work requiring extremely specialized skill and tools...but an AMAZING result. Wow. Big thanks for posting this. Outstanding again!!

[ash77]

WOW! But im not sure if I dare to do that.

[dadog13]

revolution in replica world...I am already counting the reps which would need this mod...

congrats!

[scoobs1971]

Great tuto, but not for the faint-hearted.... Would be awesome if somebody could produce the ring and prepared dial in batches and sell it as a mod kit.

[Ronin]

That was excellent. Make a kit!!!

[tazzman]

this is really interesting.. as a service ..

this + chiefs AR .. wooho!

gen hand and dials are not for me but this obvious problem needs to be fixed on many models..

[Francisco]

At the moment I need to rest. Last days I have been working hard on this mod.

I do not know if i can offer this mod. If so, I needed to think of making the parts faster.

Francisco

[chrgod]

Really impressive!

[triplehd]

HOLY F*@&$* SH%(#

THIS IS AWESOME !!!! Now I can re-purchase the UPO Chrono.

Please Francisco please offer this mod !!!!!

[triplehd]

BTW - Can a 7753 movement fit the modded 7750 UPO Dial layout?

[db1]

amazing work and research! thumbs up francisco ! i always love seeing those threads

i believe he would not be able to offer this mod to the masses, but if a batch of rings & DW could be made and sold as a "DIY" kit i believe many members would love to get their hands on them !

work of art ! keep it up

[andreww]

Outstanding result! I had no doubt that you could pull this of F, but like I gathered, its a lot of work and likely won't be offered to the masses.

[RickHiC]

Magnifique!

I had thought of adding an additional datewheel over the top of the gears, but only as a passing thought. Obviously the difficulty is in the tiny tolerances. Anyway, now you've got a nice length of the finalized steel washer to work with. Is it easier if you slice it into a more manageable widths (say 1mm), then sand or lathe those down to the critical 0.4mm?

If you can figure out how to mass produce this mod, you will have a line as long as chieftang's. Name a fair price

[Francisco]

Is it easier if you slice it into a more manageable widths (say 1mm), then sand or lathe those down to the critical 0.4mm?

It is difficult to fasten that ring in the lathe.

Thanks for your comments...

Francisco

[hackR]

as cool as ninjas!...

Great work, F...

[deltatahoe]

not much else to say other than wow

this is the kind of thing that makes this hobby interesting -- people always striving to make improvements and try new things.

puts the boring "i just bought this fancy new watch with my mastercard" to shame (not to say that there isn't a time and/or place for that)

deltatahoe

[hpy540]

Bravo,............ excellent mod.

can you send me the dimenstions. i got the .p038 mm but the ID and OD. I used to work in a machine shop to make missle parts for the military. I used to make some stuff like this. The shop is still here. I can check into gettin some of these made.

[jeff g]

Francisco your contributions to this forum is what RWG is all about.

Thank you for a great thread. We are lucky to have members like you.

[siesta181]

Wow... If only Francisco can sell the ring.

I am quite sure the rest of us will have the resources to do the rest

[alt.watch.obsessive]

Wow! That's so impressive I'm going to read it again after this post!

Would it be possible to find a flat gasket of the right dimensions to use in place of the metal spacer? I once had to find a way to keep a crystal clear of the hands on a vintage watch, and used this method. What would the inner and outer dimensions need to be?

[Shundi]

Great tuto, but not for the faint-hearted.... Would be awesome if somebody could produce the ring and prepared dial in batches and sell it as a mod kit.

Agreed..if this was mass produced and sold for $100-200 it'd fly off the shelves... Bravo- great tutorial and an amazing write-up!

[Francisco]

Bravo,............ excellent mod.

can you send me the dimenstions. i got the .p038 mm but the ID and OD. I used to work in a machine shop to make missle parts for the military. I used to make some stuff like this. The shop is still here. I can check into gettin some of these made.

Sorry people. I do not why this weekeng I had strong problems to connect to RWI from my house.

Outside diameter 24.5 or 24.6 mm.

Inside diameter: the wall of the ring is about 0.35 mm.

Widht (height). You can choose several options, taking into account that the total height of ring + DW is 0.8 mm or better less than 0.8 mm. Minimum height for the ring is about 0.45 mm.

Francisco

[Francisco]

Wow! That's so impressive I'm going to read it again after this post!

Would it be possible to find a flat gasket of the right dimensions to use in place of the metal spacer? I once had to find a way to keep a crystal clear of the hands on a vintage watch, and used this method. What would the inner and outer dimensions need to be?

I tried several weeks before glass gaskets. You can find the correct diamaters (out, in). However the height is too large and it is extremenly difficult (if possible) to reduce the height without deforming the gasket. A deformed gasket will stop the DW...

Francisco.