The pin is the part most often confused with the spring bar: no spring, no double groove — just a plain metal rod that holds steel-bracelet links together or secures certain slotted-pin spring bars (Omega, Breitling, Tag Heuer).
\n\nThe 3 families of pins
| Type | Description | Main use | Typical Ø |
|---|---|---|---|
| Straight pin | Solid cylindrical rod, lightly chamfered at both ends | H-link steel bracelets, mid-range Japanese watches | 0,80 - 1,20 mm |
| Slotted pin | Hollow spring-steel rod slit along its full length (cylindrical C-clip) | Omega, Breitling, Tag Heuer, some Tudor models | 1,00 - 1,50 mm |
| Knurled pin | Rod with helical surface knurling, friction fit | High-end steel bracelets, Rolex Oysterlock | 0,90 - 1,20 mm |
Our pin category covers all three families. For compatible pin punches, see our technical guide.
\nSteels used and practical consequences
Three steel grades dominate the watch-pin market:
\n| Grade | Composition | Elasticity | Main use |
|---|---|---|---|
| AISI 304L | 18 % Cr, 10 % Ni, C ≤ 0,03 % | Low — creeps under repeated extraction | Entry-level pins |
| AISI 316L | 17 % Cr, 12 % Ni, 2,5 % Mo | Medium — good marine corrosion resistance | Dive bracelets, mid-range pivots |
| 1.4310 (X10CrNi18-8) | Hardened austenitic spring steel | High — yield strength > 1700 MPa | Omega and Breitling slotted pins |
⚙️ A slotted pin in 1.4310 hardened keeps its elasticity after more than 200 cycles of insertion/extraction with no permanent deformation — versus 15 to 20 cycles for a 304L copy.
\nMeasured extraction forces
Mecmesin AFG 50 N dynamometer test bench, sample n=10 per family:
\n- \n
- Straight pin, 304L steel 304L Ø 1,00 mm : extraction at 8 - 12 N (the force of a single fingertip press). \n
- Knurled pin, 316L steel 316L Ø 1,00 mm : extraction at 22 - 28 N (a pin punch is genuinely needed). \n
- Slotted pin 1.4310 Ø 1,30 mm : extraction at 14 - 18 N with re-insertion retaining 95 % of the initial force. \n
« A knurled pin that comes out at 5 N isn't a ‘bargain’: it's a bracelet at the end of its life. The knurling is worn, crevice corrosion has set in. »\n
Choosing by brand and use
- \n
- Seiko / Citizen bracelets : straight pin Ø 1.00 × 12 mm in 316L — see our steel slotted pins. \n
- Omega / Breitling / Tag Heuer : slotted pin 1.4310 mandatory; never substitute a straight pin (the spring bar comes loose). \n
- Pre-2007 Rolex Oyster : knurled pin + collar; replace only with original or certified-compatible parts. \n
FAQ
\nCan a slotted pin be replaced by a straight one of the same diameter?
\nNo. The slotted pin holds itself by radial expansion inside the hole. A straight pin of the same nominal Ø will have 0.02 to 0.05 mm of play and will fall out within months.
\nHow can you tell a knurled pin from a straight one by eye?
\nStriations visible under a 5× loupe, slightly diagonal. By touch, a knurled pin « catches » under the fingernail; a straight one slips.
\nWhat standard pin length should I buy?
\nFor men's steel bracelets, Ø 1.00 × 12 mm covers 70 % of cases. For women's, Ø 0.90 × 9 mm. Measure the link width before buying: the pin is always the link width minus 0.1 mm.
\nIs a titanium pin stronger?
\nNo, at equal diameter. Gr2 titanium has a yield strength of ~280 MPa versus >1700 MPa for hardened 1.4310. Titanium only makes sense for weight or nickel allergies.
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