Box of slotted pins Ø 0.9 mm, 4–21 mm

This assortment gathers 360 watch pins of the split type, 0.9 mm diameter, in lengths from 4 – 21 mm. This box covers 18 different lengths spanning the 4 mm – 21 mm range, with approximately ≈20 units per length, for a total of 360 pieces. A split pin (or slotted pin) is a cylindrical pin with a longitudinal slit; once driven into a link, the two halves spring outward and lock the pin inside the link without any screw or knurling.

Product overview

Split pins are typically used to link the central rows of folded steel bracelets (Citizen, Casio, Seiko, Festina, mid-range Lotus, Pulsar) and the links of certain modular straps. Because their retention force comes from a sprung longitudinal slit, they are reusable a few times but a worn-out split pin should always be replaced rather than re-driven, otherwise it can pop out under daily wear and you may lose a link or the whole bracelet. The 0.9 mm diameter in this box is one of the two main calibres for fashion and tool watches.

Technical specifications

• Component type: split pin
• Diameter: 0.9 mm
• Length range: 4 – 21 mm
• Pieces per box: 360
• Material: stainless steel
• Finish: brushed / mirror polish on heads
• Storage: compartmented plastic case with hinged lid

• 4 mm
• 5 mm
• 6 mm
• 7 mm
• 8 mm
• 9 mm
• 10 mm
• 11 mm
• 12 mm
• 13 mm
• 14 mm
• 15 mm
• 16 mm
• 17 mm
• 18 mm
• 19 mm
• 20 mm
• 21 mm

When to use it

Reach for this box whenever you notice that a bracelet or strap no longer holds firmly between the lugs, when the side play of a link has become visible, when a bracelet had to be resized in the past and the original pin was lost or bent, or simply when a customer brings in a watch whose retention component is missing. The 4 – 21 mm range covers virtually every adult wrist watch on the market and most ladies' references; it is comfortable for 18-, 19-, 20-, 21- and 22-mm lug widths, the four most common in the industry. Professional watchmakers will appreciate having every length on hand without re-ordering; enthusiasts will value the freedom to swap a strap for a fashion change without paying boutique prices for a single replacement pin.

How to use / install

1. Identify the link to be re-pinned and note the direction of the arrow stamped inside the link (knurled or split pins must be driven in the direction of the arrow).
2. Lock the bracelet into a bracelet holder, with the link sitting above the holder's slot.
3. Place the pin punch (Stiftaustreiber / botador / cacciaspine / pendrijver in the native terminology) on the pin tip and drive it out with the watchmaker's hammer using light, controlled taps.
4. Slide the new pin from this assortment into the link, knurled or split end first, and tap gently with the watchmaker's hammer until it sits flush with the outside face.
5. Inspect the joint visually and flex the link: if any play is felt, replace the pin with a fresh one of the same length.

Quality & origin

Each piece is machined from stainless steel (typically AISI 304L or 316L grades depending on the production batch), bright-finished and passivated to resist sweat and skincare residues. The spring bars feature hardened spring steel inside the body, with a calibrated spring rate that keeps the tips engaged even under the shocks of daily life. Knurled pins are work-hardened in the knurling zone so they hold their grip after several removals. Our boxes ship from European stock with a per-size visual control and a length tolerance kept within ±0.1 mm.

FAQ

How do I measure the right length?

With a digital calliper, measure the inside lug-to-lug width of your watch case, then subtract approximately 0.1–0.2 mm — that is the spring bar length you need. For pins driven into a steel bracelet, measure the existing pin or the width of the link from the outside.

Are these compatible with my Rolex / Omega / Tudor?

Yes for the diameter that matches your reference: 0.9 mm fits most Submariner-, Datejust-, Speedmaster- or Black Bay-style cases that use generic spring bars. For original Rolex / Omega service, the OEM-coded part may be required by warranty. These pieces are non-OEM but dimensionally compatible.

Can I reuse a pin after removing it?

A spring bar may be reused as long as its tips still spring freely and have not been chamfered by repeated tool marks. A watch pin of split or knurled type loses grip after one or two removals and should be replaced to avoid losing the link in service.