A two-pin case wrench for opening screw-back cases on diving and sport watches.
Product overview
This watchmaker tool is a two-pin wrench designed to open and close screw-back cases on diver-style watches. It engages directly with the notches of the case-back and converts steady hand torque into a secure rotation. Sized to fit most cases from 18 to 54 mm including many Seiko, Tissot and homage Rolex Submariner references, it is essential for battery changes, gasket renewal and movement extraction. Owning the proper instruments is the first step toward enjoyable, repeatable watch servicing on the bench at home or in a professional workshop. This watchmaker tool belongs to a broader range of horological accessories trusted by amateur restorers, vintage watch collectors and professional repair benches alike. Every stage of a watch service from case-back removal, gasket inspection, movement cleaning, bracelet sizing to crystal pressing benefits from dedicated, correctly sized instruments. Investing in the right tool prevents costly scratches on polished bezels, broken lugs, sheared screw heads or damaged spring bars. Whether you service a Seiko 5, an Omega Speedmaster, a Rolex Submariner clone or a Bergeon-compatible reference, working with proper hand tools dramatically reduces the risk of damaging your timepiece. Many enthusiasts start with battery changes on quartz watches and gradually move to bracelet adjustments, then case-back openings, before attempting movement work. Each phase needs its own specialised instruments, and assembling a full kit over time is more economical than buying a closed boxed set. Always work on a clean, well-lit bench, ideally on a soft mat that catches small parts, and keep a magnetic tray nearby for screws and pins. Lubricants like Moebius oils, drying papers and a dedicated dust blower complete the typical workshop. Combine this item with a watch holder, a 10x loupe and a fine screwdriver set ranging from 0.6 mm to 2.0 mm for a fully functional repair station. The hardness of working surfaces is calibrated around 55 to 60 HRC on most professional benches, ensuring repeatable results without marking the workpiece. Used carefully and stored away from humidity, this watchmaker tool will support hundreds of services without significant wear, and will pay for itself after only a few interventions on quartz or mechanical calibres. The bench is the heart of any watch service: a stable holder, focused light, soft work mat and tidy parts tray make every operation safer and faster. Adding this watchmaker tool to that environment turns a casual workspace into a small atelier capable of professional results on quartz and mechanical calibres alike. The bench is the heart of any watch service: a stable holder, focused light, soft work mat and tidy parts tray make every operation safer and faster. Adding this watchmaker tool to that environment turns a casual workspace into a small atelier capable of professional results on quartz and mechanical calibres alike.
Technical specifications
- Steel adjustable arms
- Three interchangeable pin tips supplied
- Adjustment range 18 to 54 mm
- Knurled steel handle
- Total length approx. 16 cm
- Suitable for steady torque application
When to use it
Use this wrench when a battery change, gasket replacement or movement service is required on any watch with a notched screw-back.
How to use
- Secure the watch in a case holder face down
- Adjust the wrench arms so the pins enter the case-back notches
- Lock the slider to fix the spacing
- Press firmly downward to keep pins seated
- Rotate counter-clockwise to open the case
- Reverse the process to close, applying steady torque only
Quality & origin
Manufactured from steel with hardened pin tips. Supplied with three pin shapes to match common notches. Used carefully it lasts many years on a hobbyist or professional bench.
FAQ
Will it fit a Seiko diver?
Yes, the 18 to 54 mm range covers most Seiko, Tissot and Submariner-style backs.
Can I open a snap-back with it?
No, snap-back cases need a knife or pry tool, not a notch wrench.
Are pins replaceable?
Yes, the three supplied tips can be swapped to match the notches.
