Oct 12, 2026Reference & Sizing
Watch Screw Size Guide: Measuring Case-Back, Movement, and Bracelet Fasteners
A lost screw is three numbers: where it goes, thread diameter, length. Case-back, movement and band fasteners with the kits that cover them - and how to size yours.
Watch Screw Sizes: Three Families and How to Measure Them
Replacing a lost or damaged watch screw begins with recognizing that horological fasteners do not follow standard consumer hardware scales, relying instead on miniature threaded fasteners spanning thread diameters from 0.8 mm to 2.0 mm. Sizing a replacement is never a matter of guesswork across a bench mat; every fastener requires three distinct geometric numbers: functional location, shank or thread outer diameter, and usable thread length beneath the head. Sizing screw threads relies on the same measuring habit, written for winding stems, but screws require tracking head geometry and overall length alongside thread diameter, measuring intact thread crests with a caliper and checking under a loupe whether the head seats flat against a counterbore or tapers into a countersink.
The Three Watch Screw Families at a Glance
Every fastener inside or outside a watch case belongs to one of three mechanical families: case-back and bezel screws, movement and casing clamp screws, or bracelet link screws. Grouping fasteners by functional role prevents ordering mismatched thread pitches or unsuitable head profiles before selecting a replacement assortment from stock.
Where it goes | Typical measuring | Catalog kits |
|---|---|---|
Case-back & bezel | Head Ø, thread/tube Ø, overall length | Case-back screw kit; Hublot-listed screw assortment |
Movement & casing clamps | Thread Ø, shank length, washer/tab clearance | 240-piece adapter kit; ETA 2836/2834/2846 screw & washer kit |
Bracelet & lug links | Tube Ø, thread length, head width | Confirm by message (cross-reference band pin kits) |
Because thread pitch varies between exterior case metals and delicate movement mainplates, fasteners cannot interchange between families. Case-back screws endure moisture exposure and shear tension, whereas movement fixing screws prioritize low-profile heads that clear oscillating weights.
Watch Case-Back Screws: Head Diameter, Shank Thickness, and Length
Watches equipped with screw-secured case covers rely on fine machine screws countersunk into case rims. Kocandy catalogs an assortment of stainless steel watch case-back screws organized across twelve distinct sizes, packaged with approximately 30 pieces per size in a compartmented plastic box. Sizing requires matching the catalog format: head diameter, tube or shank diameter, and overall thread length in millimeters.
Assorted stainless steel watch case-back screws in twelve stated sizes.
The twelve stated case-back screw sizes span head diameters from 1.4 mm to 2.0 mm, thread diameters from 1.0 mm to 2.0 mm, and lengths from 1.5 mm to 2.5 mm. Specific combinations include 1.4 x 1.0 x 2.0 mm, 1.4 x 1.0 x 2.5 mm, 1.5 x 1.0 x 2.0 mm, 1.5 x 1.0 x 2.5 mm, 1.6 x 1.0 x 2.0 mm, 1.6 x 1.0 x 2.5 mm, 1.6 x 1.2 x 1.5 mm, 1.6 x 1.2 x 2.0 mm, 1.6 x 1.2 x 2.5 mm, 1.8 x 1.4 x 2.5 mm, 2.0 x 1.2 x 2.0 mm, and 2.0 x 2.0 x 2.5 mm. Thread length must match blind hole depth to avoid bottoming out.
Watch Movement Fixing Screws, Casing Clamps, and Dial Adapters
Movement fixing screws clamp the caliber firmly inside the case, preventing dial shifting when operating the winding crown. Because movement mounting geometry varies across calibers, always identify the caliber before ordering movement screws or casing tabs. In many watches, movement clamps use offset dog-leg washers or tabs bridging the gap between the mainplate and casing ring.
Movement fixing adapters and casing clamp securing screws in compartmented storage.
To service loose movements, Kocandy supplies a 240-piece movement fixing adapter set in stainless steel, providing casing clamps paired with securing screws spanning adapter lengths from 3.1 mm to 5.7 mm (stated as 12 sizes in the title and 10 sizes in description text). For dedicated calibers, model SP0003458 supplies movement adapter screws and washers for ETA calibers, listed for ETA 2836, 2834, and 2846 movements with ten washer sizes and two dedicated screw sizes.
Micro Watch Screws: Assorted Replacement Kits Compared
General repair benches require micro-screw assortments to replace missing bridge, battery clamp, and dial foot screws. The 1000-piece micro screw assortment under model WSET-ZH-S-0018 supplies eighteen stainless steel specifications in a plastic box: nine Type A pointed-tip sizes (thread diameters 1.0 mm to 1.4 mm) and nine Type B flat-tip sizes (uniform 1.2 mm thread diameter across lengths from 1.6 mm to 5.5 mm).
Kit | Stated sizes / detail | Count | Stated material | Product link |
|---|---|---|---|---|
1000-Piece Micro Assortment (WSET-ZH-S-0018) | 18 sizes: 9 pointed (1.0–1.4 mm Ø), 9 flat (1.2 mm Ø, 1.6–5.5 mm length) | 1,000 pcs (stated) / 18 types | Stainless Steel | |
10-Size 1.2 mm Screw Kit (SP0000061) | 10 lengths: 1.6 mm to 6.0 mm at approx. 1.2 mm thread diameter | Approx. 600 pcs (60 pcs/size) | Stainless Steel | |
12-Size Assorted Screws Kit | 12 sizes; sample labels 1.4x1.2x3.5, 1.6x1.2x4.5, 2.0x1.2x4.5 mm | Approx. 720 pcs (60 pcs/size) | Stainless Steel | |
Hublot-Listed Screw Assortment | 12 sizes: 2.0–2.5 mm head, 1.2–1.4 mm thread, 2.0–8.5 mm length | Approx. 140 pcs | Stainless Steel | |
Case-Back Screws Assortment | 12 sizes: 1.4–2.0 mm head, 1.0–2.0 mm tube, 1.5–2.5 mm length | Approx. 360 pcs (30 pcs/size) | Stainless Steel |
Model SP0000061 ten-size screw kit spanning 1.6 mm to 6.0 mm lengths at 1.2 mm thread diameter.
For repairs requiring standard 1.2 mm threads, model SP0000061 provides a 10-size assorted watch screws kit containing approximately 600 stainless steel screws across ten lengths: 1.6, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, and 6.0 mm. Additionally, Kocandy offers a 12-size assorted watch screw kit containing approximately 60 pieces per size, allowing incremental test-fitting without stripping brass movement threads.
Watch Band and Bezel Screws: Dedicated Screws and Thread Pitch
Fasteners used on watch bezels, case lugs, and bracelet links face heavy shearing loads and environmental exposure to sweat and water. Luxury sports watches often utilize distinctive decorative fasteners with proprietary drive profiles or specific thread diameters. For bezel and strap maintenance, our catalog lists an assortment of stainless steel screws for Hublot-style watches containing approximately 140 pieces across twelve stated sizes, including head diameters of 2.0 mm, 2.3 mm, and 2.5 mm, thread diameters of 1.2 mm and 1.4 mm, and lengths ranging from 2.0 mm to 8.5 mm. When servicing metal bracelets, threaded link screws must not be confused with friction pins or split pins; always measure link tube width and screw thread diameter prior to replacement.
Stripped and Seized Watch Screws: Extraction Techniques and Tools
Damaged screw heads represent a frequent bench hazard when screwdriver blades slip under torque. Loosening a stubborn screw requires a blade filling 90 to 95 percent of the slot width, detailed in our watch screwdriver blade sizing guide. For screws with seized threads or damaged heads sitting proud of the plate, mechanical extraction tools provide controlled torque without gouging surrounding movement bridges.
Situation | Method (hedged) | Tool |
|---|---|---|
Stripped slot, proud head | Radial clamping around perimeter | 3-in-1 screw repair plier (1.4, 1.0, 0.7 mm apertures) |
Seized case-back thread | Capillary penetrating fluid; blade matching | Penetrating oil; matched hollow-ground screwdriver |
Sheared shank below bridge | Chemical dissolving or specialist milling | Confirm by message (bench extraction / replacement bridge) |
Threadlocker resistance | Controlled pinpoint heat to break bond | Warm brass probe or clean iron tip |
Three-in-one screw repair plier featuring copper handle and interchangeable steel mouth apertures.
Kocandy provides a 3-in-1 watch screw repair plier featuring a copper handle and interchangeable hardened steel jaws. The tool supplies three aperture dies stated at 1.4 mm, 1.0 mm, and 0.7 mm (listed in detailed specifications as 1.4 mm, 1.1 mm, and 0.8 mm). The circular aperture encircles the exposed head or shank, exerting radial clamping grip where flat pliers slip. For seized threads, apply a micro-droplet of penetrating oil and allow capillary action to loosen debris before applying mechanical torque.
Balance Wheel Timing Screws: Caliber-Specific Micro-Adjustments
High-grade mechanical movements featuring free-sprung balances utilize micro-screws threaded directly into the balance wheel rim to regulate rate and poise, adjusting inertia without disturbing the hairspring. For specialized servicing, Kocandy lists an alloy steel watch adjustment timing balance screw tool with a knurled metal mesh handle measuring 88 mm in length and 6 mm in diameter. The tool is cataloged for Audemars Piguet AP 3120 and 3126 calibers as well as Patek Philippe PP 324-S movements. Because rim screws sit adjacent to delicate pivots and hairspring coils, these adjustments require specialized micro-drivers, rigid hand rests, and high magnification.
Sizing Your Watch Screw: How to Send Us Your Measurements
When ordering replacement watch screws from Kocandy, record four core identifiers with a digital caliper: threaded shank diameter, total length beneath the head, maximum head diameter, and functional location. If the original screw is missing, measure bridge thread diameter or case-hole depth using caliper depth blades. A sharp macro photograph of the remaining screw beside a millimeter ruler or caliper jaws verifies head profile and thread pitch.
Kocandy is not affiliated with, authorised by, or an official dealer for any watch manufacturer, including Audemars Piguet, Patek Philippe, Hublot, ETA, Rolex, Seiko, or Omega. All brand designations mentioned refer strictly to aftermarket workshop compatibility or stated-for catalog specifications. If you need a replacement fastener, match your readings against our catalog kits above or reach out directly through our contact form. We reply within one working day. If your size, caliber, or reading is not listed anywhere above, send your caliper measurements anyway and we will check them against the catalog.
