Clean GMT Master II Crystal Gasket rework

[kino0924]

Hi, I am considering of changing crystal gasket from CF GMT Master II 126710

Best approach will be swap gen crystal but its hefty investment and I would like to try one thing first.

So, my purpose is to fix cyclops magnification.
I really don't mind the quality of CF crystal but the magnification bothers me the most.
Gen is more like 2.5x and CF looks like 3x.
My understanding is CF GMT uses a 2.95mm gasket and a 1.65mm crystal in its stock config.

So these are my questions
1. If I change crystal gasket to 2.5mm or 2.7mm gasket, will it reduce the magnification more like gen?
2. Where can I get press for crystal retaining ring? I heard some uses old YM bezel but I do not have it. I need a place where I can just buy from online.

Thank you!

 

[hungaryrolex]

Hello,

I recommend getting Deep Crystal and using Clean Gasket with it.
If you spend a little more time and energy, you can buy an aftermarket crystal gasket.

There are cheaper and less cheaper solutions for replacing the xtalt compression ring.
For a few euros and with a small measurement, you can make or have a 3D printed ring made, which you can press using a press. (must be printed in hard plastic
But there are also official tools for such restoration.

(I recommend the 3d printed ring)

 

[kino0924]

Hello,

I recommend getting Deep Crystal and using Clean Gasket with it.
If you spend a little more time and energy, you can buy an aftermarket crystal gasket.

There are cheaper and less cheaper solutions for replacing the xtalt compression ring.
For a few euros and with a small measurement, you can make or have a 3D printed ring made, which you can press using a press. (must be printed in hard plastic
But there are also official tools for such restoration.

(I recommend the 3d printed ring)

Thank you so much for the super fast reply.

I may end up using deep xtal but I wanna try this first for few reasons.
1. Very Cheap (only replacing gasket)
2. I also want to make flush fit of crystal and bezel.

As you can see from this image, Clean's crystal sits like 0.1-0.2mm higher than Gen.
So I thought, by replacing shorter gasket, it will make crystal to sit flush with bezel and also reduce magnification.

All the information that I gathered from RWI/Reddit is that,
There will be a problem with water proofing (according to Noleex_The_Modder from reddit)
Second hands might rub crystal due to shorter gasket and Clean's GMT second hand sits higher than gen.

On the other hand, which material should I use if i 3d print for the ring?
I have access to 3d printer from my local area but not sure if material is suitable for this case.
And, lastly, do you have 3d model file?


Thank you so much!!

 

[kino0924]

Correct me if im wrong

( https://www.reddit.com/r/RepTime/comments/y1gcrd/_/irx783r )
Gen : 2.68mm gasket + 1.8mm xtal = 4.48mm total
CF : 2.95mm gasket + 1.65mm xtal = 4.60mm total

Or This
( https://www.reddit.com/r/RepTimeServices/comments/17aybuz/_/k5fz4ba )
Gen : 2.25mm gasket + 1.8mm xtal = 4.05mm total
CF : ?.??mm gasket + 1.58mm xtal = ?.??mm total

With mixed information from online, I am not sure 'real' thickness of gen gasket (at least xtal info is unified that its 1.8mm)

 

[kino0924]

Ahhh, I hate formatting issue
Correct me if im wrong

Info1
Gen : 2.68mm gasket + 1.8mm xtal = 4.48mm total
CF : 2.95mm gasket + 1.65mm xtal = 4.60mm total

Or This
Info2
Gen : 2.25mm gasket + 1.8mm xtal = 4.05mm total
CF : ?.??mm gasket + 1.58mm xtal = ?.??mm total

With mixed information from online, I am not sure 'real' thickness of gen gasket (at least xtal info is unified that its 1.8mm)

 

[KJ2020]

Both gen gasket heights are correct. CF crystal is 1.60mm

2.7mm gaskets are for previous generation crystals B25-295-CAR-C1 (AR under cyclops only)

2.25mm gaskets are for newest generation crystals 7035-1-C1 or J1 (AR on full underside)

Whatever crystal you use, it is true that a shorter gasket will decrease date mag and ofc the crystal will sit lower. So it's all a compromise. I strive for desired date mag first, then crystal sitting height. If the second hand touches the crystal the hand collar can be sanded to a shorter height BUT with rep 4 hand stacks this can snowball on you. You can only lower the second hand as far as the minute hand will allow.

Which crystal gasket should I use?

Crystal gasket shave - DIY

Custom Rolex crystal gasket height

Second hand catching on crystal

 

[kino0924]

Both gen gasket heights are correct. CF crystal is 1.60mm

2.7mm gaskets are for previous generation crystals B25-295-CAR-C1 (AR under cyclops only)

2.25mm gaskets are for newest generation crystals 7035-1-C1 or J1 (AR on full underside)

Whatever crystal you use, it is true that a shorter gasket will decrease date mag and ofc the crystal will sit lower. So it's all a compromise. I strive for desired date mag first, then crystal sitting height. If the second hand touches the crystal the hand collar can be sanded to a shorter height BUT with rep 4 hand stacks this can snowball on you. You can only lower the second hand as far as the minute hand will allow.

Which crystal gasket should I use?

Crystal gasket shave - DIY

Custom Rolex crystal gasket height

Second hand catching on crystal

The GOD of GMT answered all my questions!!!
I'm gonna try with 2.85mm and 2.7mm gasket and see which one works for my taste!

Thank you so much!!!

 

[KJ2020]

I'm gonna try with 2.85mm and 2.7mm gasket and see which one works for my taste!

Thank you so much!!!

Some other threads you might find useful

Tutorial: How to fix the Bezel on a CLEAN GMT

6-digit GMT bezel install sequence

6-digit Sub crystal and bezel swap

Post back if you run into issues or to show off your results

 

[kino0924]

Just purchased Clark 2.85mm and 2.7mm gasket.
Will post the result when it arrives.

 

[FiliGelli]

After many trials i can say that cf crystal has to go with stock cf gasket only otherwise you cant fit the crystal holder as stock cf gasket is thin and soft, way different from gen/aftermarket gaskets(thicker and harder).
Cf gasket has also a sort of curve at the edge that stays near to the case.
That curve matches exactly the shape of the stock crystal holder.
That's the reason why it's really hard to achieve the waterproof if you swap gasket.
If you try to shave the stock gasket in order to achieve gen crystal height you will end up losing the waterproof.
Furthermore you have to consider also the tension of the crystal holder as if you press it on a gen gasket you risk to compromise the bezel turning.
If you want to go in the crystal/gasket mod direction you have to be prepared to try many different combo until you find the right one as cf mid cases are not all identical too...
It's a fucking mess...

 

[LostinHifi]

Just purchased Clark 2.85mm and 2.7mm gasket.
Will post the result when it arrives.

Any update on which gasket you used finally?

 

[mhrboy]

Interesting thread.
As alternative, someone tried a VSF crystal?
I got a VSF crystal + gasket coming from datejust 36mm but don’t have skills to try it. Is it suitable on Clean GMT?

 

[ffnc1020]

Any update on which gasket you used finally?

I recently tried gen crystal with Clark 2.7 and gen 2.7 gasket, both doesn’t work and the second hand rubs on the crystal. What I did was shave down the clean crystal to about 2.78 and it worked for me. I think the overall hand stack height varies from one example to another.

 

[kino0924]

Any update on which gasket you used finally?

i have gaskets on my hand but I do not have proper tool to press crystal retaining ring yet.
Im trying to source explorer2 bezel for this purpose.
Also, I think I am going to order deep crystal as well as 2.5mm Clark gasket because I saw some report that this is best mag+flush.

Interesting thread.
As alternative, someone tried a VSF crystal?
I got a VSF crystal + gasket coming from datejust 36mm but don’t have skills to try it. Is it suitable on Clean GMT?

My understanding is DJ36 crystal is interchangeable with GMT2 Crystal.
Thus, it should be one of good combo since VSF crystal is known to be better than CF crystal.

I recently tried gen crystal with Clark 2.7 and gen 2.7 gasket, both doesn’t work and the second hand rubs on the crystal. What I did was shave down the clean crystal to about 2.78 and it worked for me. I think the overall hand stack height varies from one example to another.

You mean you shave down clean crystal gasket not crystal right?
I saw people use gen hands due to second hand rub on the crystal.

This is known issue for people who uses gen crystal + gen gasket (7035)
The solution is either use gen hand, or shave down second hand.
If second hand touches crystal, ill prob shave down second hand as well.

@KJ2020 already posted greate guide for us

GMT crystal sits too low to clear the second hand

So the crystal sits too low on your GMT for whatever reason and the second hand is hitting its underside. You want to keep the gasket and crystal like they are and try to lower the second hand on its pinion. Can this be done safely? The first thing I would try is a different second hand. The...

forum.replica-watch.info

I truely believe @KJ2020 is master of GMT2.
All the information is out there already but its just shattered all over the places lol

 

[kino0924]

@KJ2020
Do you know if gen 126710 been always 7035 or some early models were 295-CAR?

 

[KJ2020]

@KJ2020
Do you know if gen 126710 been always 7035 or some early models were 295-CAR?

The first 126710 BLRO GMT was released in 2018. It had the 3285 movement and the B25-295-CAR-C1 crystal. The full underside AR crystals were released with the Sept 2020 introduction of the 126x Subs. So the GMTs would have switched to those crystals around that time or shortly after.

We can use a B25-295-CAR-C1 crystal in a 126x GMT without concern for period incorrectness, except for the latest models like Sprite and the GRNRs.

 

[ffnc1020]

You mean you shave down clean crystal gasket not crystal right?
I saw people use gen hands due to second hand rub on the crystal.

This is known issue for people who uses gen crystal + gen gasket (7035)
The solution is either use gen hand, or shave down second hand.
If second hand touches crystal, ill prob shave down second hand as well.

@KJ2020 already posted greate guide for us

GMT crystal sits too low to clear the second hand

So the crystal sits too low on your GMT for whatever reason and the second hand is hitting its underside. You want to keep the gasket and crystal like they are and try to lower the second hand on its pinion. Can this be done safely? The first thing I would try is a different second hand. The...

forum.replica-watch.info

I took a second crack at this and was able to achieve the flush look with Clark 2.5mm gasket and gen B25-7035-4-C1 crystal. Had to shave all four hands a bit. The second hand post is already just 1mm tall but still touching the crystal. Had to bring it down a bit more after many trails. It’s a painful process.

 

[Mark1937]

I took a second crack at this and was able to achieve the flush look with Clark 2.5mm gasket and gen B25-7035-4-C1 crystal. Had to shave all four hands a bit. The second hand post is already just 1mm tall but still touching the crystal. Had to bring it down a bit more after many trails. It’s a painful process.

in gen 126710 the glass is not flush! It always protrudes a little from the bezel

 

[Mark1937]

My full franken with gen new 2xA/R crystal with 2.70 gasket. Height and magnification are perfect, gen like! (all obviously shared during the construction phase with the Master kj2020 )

 

[Sir_Maxelot]

I have a brand new Clean 126710 and new gen 7035 crystal with gen gasket lying here.
Can anyone recommend a combination of parts that work?
Some comments say the genuine gasket won’t fit, but others seem to have made it work?!
I am confused