Why use a crystal press
Replacing a watch crystal requires evenly controlled pressure. The crystal press ensures a clean fit without cracking the crystal or distorting the bezel. It is indispensable for crystals fitted with a crystal gasket.
Installation steps
- Open the watch and remove the movement to protect the calibre.
- Measure the case and confirm the replacement crystal is the right size.
- Select the lower die: choose a straight-walled die matching the diameter of the case back. The edges must clear the lugs.
- Install the lower die on the lower post of the press.
- Select the upper die: it must sit on the outer edge of the crystal, with straight walls facing inward.
- Fix the upper die on the upper post of the press.
- Protect the case with a lint-free cloth on the lower die.
- Position the case on the lower die, opening facing up.
- Place the crystal on the bezel opening with the gasket in place.
- Check the alignment by closing the jaws without applying pressure.
- Apply pressure gradually by operating the handle until you feel the click of engagement.
- Inspect the crystal: it must sit flush with the gasket evenly compressed.
Technical tips
If the crystal does not snap in, do not force it: inspect it under a loupe. A chip on the edge or a wrongly sized die explains the resistance. Re-measure and adjust the die.
Required tools
- Watch crystal press with die set
- Digital caliper
- Lint-free cloth
- Watchmaker tweezers
- x5 or x10 loupe
Find these tools in our watchmaking tools section and the matching gaskets in crystal gaskets.
Replacing the crystal without replacing the gasket only delays the leak by a few months.
Common mistakes to avoid
- Re-using a scratched crystal for the sake of economy
- Keeping the old crystal gasket
- Underestimating the press force required
FAQ
Which die should I pick for the top?
A die whose straight inner walls rest just on the outer edge of the crystal, without overhang.
Should I grease the crystal gasket?
No. Unlike a case gasket, the crystal gasket does not need silicone grease.
What if the crystal breaks?
Check that the pressure is evenly spread and that the new crystal has no chip on its edge. A die too small creates stress points.
Will the case remain water-resistant after replacement?
Yes, provided the gasket is new, clean and evenly compressed. Also check the case-back gasket.