The crystal and case-back press is the workshop standard for seating mineral or acrylic crystals and closing snap-on case-backs with controlled, uniform pressure. It replaces the hammer for precious cases and high water-resistance ratings.
Product overview
The press uses a lever-driven plunger that applies vertical pressure between two dies. The lower die supports the watch case while the upper die pushes the crystal or the case-back home. A complete set of nylon dies covers the most common diameters, from ladies' dress watches to oversized divers.
Technical specifications
- Body: machined metal, painted black
- Lever: ergonomic
- Dies: set of 12 to 18 nylon dies, 14 to 50 mm
- Height: 240 mm
- Weight: 1.4 kg
- Use: fitting crystals and snap-on case-backs
- Compatible with all watch sizes
When to use it
Use the press for any fitting that requires uniform pressure: mineral crystal seating, acrylic crystal compression, snap-on case-back closing on a rated diver, gasket compression on a precious dress watch. The press is also indispensable for fitting crystal gaskets on vintage Rolex Oyster references.
How to install / how to use
Select the lower die slightly larger than the case, and the upper die slightly smaller than the crystal or the case-back. Mismatched dies will damage the watch.
- Place the lower die on the press base.
- Position the watch on the lower die, crystal up or case-back up.
- Select the upper die and mount it on the plunger.
- Lower the plunger gently until it touches the crystal/case-back.
- Apply firm, progressive pressure with the lever.
- Release and inspect the seating.
- Test water resistance if applicable.
Materials and compatibility
Watch gaskets exist in several elastomer families, each with its own properties. NBR (nitrile butadiene rubber) is the most common and offers good resistance to oils and ageing. FKM (also marketed as Viton) withstands higher temperatures and aggressive solvents, and is the preferred choice for professional dive watches. EPDM resists ozone and weathering and is often found on sport models. Hytrel, a thermoplastic elastomer, is used on certain Rolex and Omega references. This tool is fully compatible with all four families, provided the gasket is lubricated with a silicone grease such as Moebius 8217.
It can be safely used on Swiss makes (Rolex Submariner, Omega Seamaster, Tissot PRX, Longines HydroConquest), Japanese makes (Seiko 5, Seiko Prospex, Citizen Promaster) and German makes (Sinn, Junghans) as long as the case-back type matches the tool's purpose. For watches rated above 10 ATM, always pressure-test after every gasket service.
Maintenance and storage
Keep the tool dry, in a clean drawer or its original sleeve. Wipe the metallic parts with a soft cloth after each use; if you have worked near solvents, dry the steel parts immediately to prevent corrosion. Inspect the working surface (tip, head or die) for marks or burrs every few months; small irregularities can be polished gently with a fine-grit abrasive cloth, but heavier damage requires replacement.
Avoid contact with strong acids, chlorinated cleaners and rubbing alcohol on plastic handles. Heat above 60 °C can soften polymer grips and reduce dimensional accuracy on precision blades — never leave the tool in direct sunlight or near a soldering iron.
Common mistakes to avoid
Three errors account for the majority of damage observed in workshops: applying excessive torque (which strips the case-back notches), using the wrong tip diameter (which slips and scratches the bezel), and forgetting to replace a hardened gasket after service (which compromises water resistance even with a fresh O-ring of the wrong size). Always work under a loupe, double-check the gasket reference before ordering a replacement, and verify the seating of the case-back before closing the watch.
A final tip from the workshop: never combine a new gasket with an old, dried-out one on a multi-seal case. If the case-back gasket is replaced, also inspect the crown gasket and the crystal gasket — they age at the same rate and a single tired O-ring will let humidity in.
Quality and origin
The press is precision-machined and supplied with a set of certified nylon dies. Spare dies and metal dies are available separately.
Frequently asked questions
Can it fit a Plexi crystal on a vintage Omega?
Yes, with the appropriate nylon dies and a thin film of compression grease.
Is it suitable for screw-down case-backs?
No, use a dedicated screw-back opener and a torque tool.
How do I clean the dies?
Wipe with a soft cloth and isopropyl alcohol after each use.
