DIY: Crystal Replacement (Speedmaster Professional Hesalite) - Picture Heavy

Hi All,

I recently replaced the Hesalite Crystal on my Speedmaster Professional and by popular demand I’ve put together a DIY. This is provided for informative purposes only – I do not take any responsibility for anyone’s actions but my own!

Note that given the cost of required tools etc. this shouldn't be viewed at as a cost saving exercise, but a fun exercise for a hobbyist - if you're not comfortable doing this, do not take apart your watch - take it to your watchmaker!

This particular watch is a Speedmaster Professional Case # 145.022 with 861 movement. I believe that you can apply the same process to sapphire crystal cases (someone please confirm/deny!).

Preparation:
As you will be opening your watch, make sure that your work area is clean, tidy, and dust-free.

Tools:
Replacing the Crystal on your Speedmaster Professional is actually a somewhat simple process as long as you have the right tools for the job:

• Spring Bar Removal Tool
• Case Opener/Wrench
• Case Holder/Case Vice
• Watchmaker’s Tweezers
• Watchmaker’s Screwdrivers
• Plastic containers or clean place to store parts
• Crystal Press/Multi Press
• I have been able to get a crystal out by hand, but getting it back in is nigh on impossible – get yourself a good press!

I tend to wear latex gloves when I open my good watches to prevent oils etc. contaminating the movement.



Step 1:
This is somewhat optional, but I prefer to work on my watches sans-strap so I get my trusty spring bar removal tool out and remove the strap.



Step 2: Case back removal.
Get your case back wrench and align the teeth with the indents on the back of the case and twist counter-clockwise. I put a thick sheet of clear plastic over the case back to prevent nicks and scratches whilst still being able to see what I’m doing.




This will expose the inside of the watch where you can see the dust cover.




Step 3: Dust cover removal.
There is a dust cover over the back of the movement which also serves a purpose of anti-magnetism and a spacer to hold the movement in-place. This cover is simply held by friction onto the back of the movement so you just pull it off.

To avoid pulling the movement out and potentially bending the crown, hold down the movement on the side opposite the crown. You can lever the cover off using a screwdriver or pull it off by hand (it depends how tight it’s on). I found that using a bit of Bergeon Rodico gum to hold the cover and pull upwards is a neat trick, but you must clean the area carefully afterwards.







Step 4: Stem and movement removal.
We now need to get the movement out so you can work on the case. The movement is only being held in-place now by the crown/stem.

To remove the stem on the 861 movement, there is a small screw that needs a few counter-clockwise turns to loosen. After a couple of turns, gently try to pull the crown and stem out straight from the case. The screw should remain where it is.






I now put the dust cover back on to protect the movement.
A safe way to remove the movement from the case is by letting gravity take over! Taking one of your plastic containers, place it upside down on top of the case and movement and invert. Hold onto the case and vice carefully. Pull the case/vice straight upwards and the movement will stay where it is. Hold onto the case and vice carefully (I can’t state this enough).





You should now be faced with something resembling this!:




There is a gasket/”O-ring” on the back of the case that should be removed very carefully so as to not damage it. Place this in a container by itself to avoid it getting stretched.

Here you can see the steel tension ring around the inside of the crystal that pushes outwards and holds the crystal firmly in place.

Step 5: Crystal removal.

With your movement, case back and gasket safely tucked away in clean plastic containers, we're ready to get on with removing the crystal.
Depending on your press, you will likely have a number of dies/casts that should fit the bill. Essentially you need something that is going to support the case by the bezel while the press pushes the crystal out.


The crystal comes out through the front of the case so place the case upside down in the correct die. My press uses plastic (Delrin) parts so it shouldn't scratch but I use bits of foam to protect my watch anyway.



Push your press down slowly but firmly, you should hear a click/pop as the press overcomes the tension ring on the crystal and it pops straight out.

You can clearly see that the old crystal (left) is worn down from polishing compared to the new one (right):

Step 6: Crystal Replacement

We now need to use the press to push the new crystal into place.

Before doing so, thoroughly clean the surface where the crystal seats and also the underside of the crystal before setting it on the case.

The best/correct die for these types of crystals is one that has slightly tapered/chamfered edges, and will have a larger diameter than the crystal. However if you're tool kit is like mine and it doesn't have one (yet!), a flat die should do the trick.

Choose a die that closely matches the outside diameter of the crystal:



The Omega crystals have an Omega logo in the middle. It is not very legible except for up-close but if you're going to do something, you should do it properly - line up that Omega logo straight!

If you're having trouble, a tip/trick you can use to keep the logo aligned once you've got it straight is by using some Bergeon Rodico to stop the crystal from moving around in the press.



Place your case on top of a suitable die that supports the case without the potential for the lugs being bent. Again, I use foam to protect my precious case. I also use clear plastic to make sure the crystal doesn't scratch.



Press the crystal down flat, level and firmly (but again, slowly) until you hear that click/pop of the tension ring holding the crystal in the case.

Now you have a new shiny crystal in your pride and joy!

While the movement is out, I took the opportunity to clean up the case with some Rodico.



Step 7: Re-Assembly

This is obviously the reverse of the disassembly. Make sure that you have thoroughly cleaned the inside of the case with a microfibre cloth. You don't want to forget this and have to take apart the watch again to get rid of fingerprints!

Take your movement and gently place it onto the lid of a container. A piece of paper/cardboard works equally as well. Very carefully, align the movement with the case and place the case on top of the movement.

Flip the case/lid over carefully so you can continue the re-assembly:



At this point, you will need to remove the dust cover from the movement (see earlier step) and re-insert the crown/stem. Once the stem is seated, tighten the stem screw and re-attach the dust cover.



The gasket which was removed earlier is a key piece of hardware to stop contaminants getting into your watch - look after it or replace it if it looks worn/damaged or if you simply want to sleep better at night.

When replacing the gasket, it needs to be lubricated to allow a tight seal, and for to stop the gasket bunching-up or stretching under the case back when tightening. One of our knowledgeable watchmaker friends on this forum, Archer uses Fomblin UT-18 grease for this application.

Gently place the gasket back in it's position on the back of the case.



At this point, it is good practice to get a loupe out and thoroughly check for signs of dirt/dust in the back of the case and clean thoroughly.

Once satisfied, you can re-attach the case back with your wrench.... And Voila!

If you look very closely, you can see the Omega symbol here on the new crystal (picture taken through loupe):



Thanks for reading! Hope this is helpful 😀

Great job, thanks for posting that 👍

Ashley

Many thanks for this instructive and interesting post. I would only make one comment - I think that, especially with a tool watch like this, it would be a good idea to renew the case back gasket (o-ring) as part of the job.

That crystal thickness difference surely can't just be due to polishing? Great article....

Disimpan

Ashley,

Many thank you's for your time and efforts!!! Well done!

Brilliant. Only need a Speedy now and I can try it.

Thanks all for your feedback, and I'm glad you enjoyed reading it. I love a good DIY 😀

John that's a good point re the gasket, though given the ease with which a case back can be removed a gasket replacement is a quick job. I might edit the post to include a reminder to inspect the gasket for damage. Mine was serviced this year so is quite new.

Mothra - I'm not the first owner of that particular Speedmaster so I can't speak to its full history. If it is the original crystal, I would think that a couple of decades of polishing could easily remove a fair bit!

Jim - I was thinking about what a watchmaker would consider "best practice" for that but I opted for leaving it in the case holder. I suppose that could actually be seen as cutting corners! My setup is actually embarrassingly simple: iPhone + shaky left hand! 😟

Oh and BTW can anyone confirm that the same theory/process can be applied to a Sapphire crystal? It would be interesting to know if you have to handle Sapphire swaps in a different way?

I can't say for sure on the Speedy, but a sapphire glass should be scratch proof. It is probably held in place by a hard plastic gasket that will need replacing or it may be glued in place using glue that cures under a UV lamp. I would suspect that it is the former on an Omega.