A watchmaker tool to open and close screw-back watch cases with three interchangeable bits.
Product overview
This watchmaker tool is a screw-back wrench supplied with three interchangeable bit shapes to engage the notches of most diver-style screw-backs. Adjustable for cases from 18 to 50 mm, it covers Seiko, Tissot, homage Rolex Submariner and many other references. The wrench transforms steady hand torque into a clean opening rotation without slipping or marking the back. 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. 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 body
- Three interchangeable bits (round / square / flat)
- Adjustment range 18 to 50 mm
- Knurled steel grip
- Total length approx. 14 cm
- Locking screw for stable spacing
When to use it
Use the wrench whenever a battery change, gasket renewal or movement service requires opening a notched screw-back case.
How to use
- Secure the watch face down in a case holder
- Choose the bit shape matching the case-back notches
- Tighten the bits in the wrench arms
- Adjust the spacing to the notch diameter
- Press down and rotate counter-clockwise
- Close by rotating clockwise with steady torque
Quality & origin
Manufactured from steel with hardened bit tips. Supplied ready to use with three bit shapes for common notches.
FAQ
Will it open a Rolex screw-back?
Yes, on Submariner-style homages and many diver references.
Snap-back too?
No, snap-back cases need a knife or pry tool.
Replacement bits?
Sold separately if a bit wears out.
