Product and application brief
This page covers the traditional loop-headed retaining pin with two adjacent legs, commonly listed as a split pin or cotter pin. It is a retaining component used with a matching drilled pin or other approved assembly, not the solid joint pin itself. A hairpin clip, tubular spring pin and traditional split pin are different constructions.
Product forms and reference names
| Product form / field | Reference and distinguishing details |
|---|---|
| Traditional split pin — ISO 1234:1997 | ISO's official catalogue identifies ISO 1234:1997 as the split-pin standard. The loop and split legs identify this product form; final geometry and acceptance requirements follow the selected reference or drawing. |
| DIN 94 catalogue reference | Bossard BN 912 lists DIN 94 with a withdrawn-standard note alongside ISO 1234. Treat DIN 94 as a catalogue reference needing clarification, not automatic proof of identical dimensions or current production conformity. |
| Material and finish variants | Bossard's catalogue distinguishes a steel, plated listing from separate stainless-steel listings. Material and finish are attributes of the selected pin, not a new retaining mechanism or evidence of FastenerBridge inventory. |
| Hairpin / R-clip — separate construction | Pivot Point distinguishes hairpin cotters and other locking cotter designs. An R-shaped spring clip is not the ordinary two-adjacent-leg split pin described here; specify the actual construction rather than requesting any cotter by name. |
Eye, paired legs and end details
Identify the looped eye, adjacent split legs and the specified tip form. Include any unequal leg lengths or special end requirements on the drawing. The illustration shows a generic uninstalled straight-leg appearance; it does not establish the standard's dimensions or an approved installed condition.
Size and length conventions
Keep the designated size, actual shank dimensions and mating-hole diameter as separate requirements. State how length is measured: overall length including the eye is not automatically the catalogue's designated length. Show the relevant datum and endpoint on the drawing rather than inferring them from a product name or picture.
Retention arrangement and separate line items
Provide the mating clevis-pin, shaft or fastener drawing and cross-hole details, with any washer or nut arrangement. List the joint pin and split retaining pin separately unless a set's composition is explicitly defined. This page does not prescribe how to bend the legs, a reuse policy, an installation process or a load rating.
Reference and substitution boundary
The official ISO catalogue and original product references establish identity and terminology only. Full normative dimensions, tolerances, material rules and DIN/ISO/ASME interchangeability have not been verified here. A change to a hairpin clip or another retainer requires review against the actual assembly, not a name-only substitution.
Specification fields
| Product form / field | Reference and distinguishing details |
|---|---|
| Identity and reference | Traditional split/cotter construction, exact standard and edition or controlled drawing/part number. |
| Size and units | Designated size and units; drawing-defined shank dimensions and tolerances where required, separate from the mating-hole size. |
| Length definition | Requested length with explicit datum and endpoint; overall length or eye-to-tip dimensions separately if needed. |
| Eye, legs and tips | Eye geometry, leg/end form, unequal-leg details and any special drawing-defined requirement. |
| Mating arrangement | Cross-hole drawing, mating-part thickness/clearance and the specified retaining arrangement. |
| Material and surface | Exact material designation, required condition and finish; shiny appearance is not material or corrosion proof. |
| Quantity and documents | Pieces by size, drawing revision, inspection/traceability and marking or packing requirements; separate component/set quantities. |
| Pending requirements | Flag missing size convention, length datum, hole details or acceptance criteria for confirmation, not assumed values. |
Common product questions
Is a split cotter pin the same as a slotted spring pin?
No. The traditional split cotter pin has a looped eye and two legs. A slotted spring pin is a hollow tube with a longitudinal slot. Informal names can overlap, so identify the structure or attach the drawing.
Does the quoted length include the looped eye?
Do not assume it does. A catalogue's designated length and overall length can use different endpoints. State the required reference and show the measurement datum on the drawing.
Can I order a hairpin clip as a direct replacement?
Not by name alone. Its construction and retaining arrangement differ from the traditional split pin. The selected assembly and controlled drawing determine whether any replacement is acceptable.
Related specification resources
Product references
References checked 6 October 2026 explain product identity. Third-party model names and approvals are not FastenerBridge brand affiliation, stock or certification claims. Final geometry and requirements follow the selected specification.