This compact keychain screwdriver is a watchmaker companion designed to open screw-down case-backs of dress watches, dive watches and chronographs without leaving the workshop. Carried on a key ring, it lets you remove a case-back gasket, inspect a crown gasket or simply check the inner crystal gasket in seconds.
Product overview
The keychain screwdriver combines two essential bench tools in a pocket format: a hardened tip that engages the notches of a screwed case-back, and a precision shaft that can also be used as a small flat screwdriver for movement screws, strap bars and battery hatches. The handle is knurled for a firm grip even with oily fingers, and the keyring loop ensures it never gets lost in a service drawer.
Designed for collectors of Rolex, Omega, Seiko and most Swiss or Japanese sport watches with a notched case-back, it is also perfectly suited to vintage divers whose Hytrel or NBR gaskets need periodic inspection.
Technical specifications
- Total length: 60 mm closed, 95 mm deployed
- Tip: hardened stainless steel, suitable for 2 and 3 mm notches
- Body: anodised aluminium with knurled grip
- Compatibility: most screw-down case-backs (Rolex-style, Seiko diver, Omega Seamaster)
- Weight: 18 g
- Supplied on stainless keyring
- Recommended torque: hand-tight only, never use pliers
When to use it
Reach for the keychain screwdriver whenever you suspect a faulty case-back gasket, a tired O-ring under the crown, or a fogged crystal gasket. It is the ideal travel tool to perform a quick inspection before a dive, a long flight or a humid trip. Many watchmakers also use it during workshop visits, fairs and brocantes to check the integrity of a watch before purchase.
Avoid using it on bezel rings, crystals or movement plates — its tip is shaped for case-back notches only.
How to install / how to use
Open the case-back in a clean, dust-free area, preferably on a soft pad to avoid scratches.
- Place the watch face down on a watchmaker's cushion.
- Align the tip with two opposite notches of the case-back.
- Apply firm but moderate downward pressure and turn anticlockwise.
- Once loose, finish by hand and lift the case-back vertically to keep the gasket in place.
- Inspect the case-back gasket, crown gasket and crystal gasket; replace any deformed or hardened O-ring.
- Lubricate the new gasket with a thin film of Moebius 8217 silicone grease.
- Re-seat the case-back, align the tip again and tighten clockwise until firm — never force.
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 keychain screwdriver is machined from hardened stainless steel and finished in Europe. Each piece is tested on a steel bench plate to guarantee tip resistance. The product is shipped in a kraft pouch with a short user leaflet.
Frequently asked questions
Can I use it on a Rolex Submariner?
Yes, the tip matches the standard 2 mm notches of most Rolex screw-down case-backs. For Oyster cases sealed at high torque, a bench-mounted opener remains preferable.
Will it damage the gasket?
No, the tool only acts on the case-back. The gasket itself is removed gently with a wooden peg, never with the metal tip.
Which grease should I use with the gasket?
We recommend Moebius 8217 silicone grease, which is compatible with NBR, FKM/Viton and EPDM O-rings.
