# R-clips (hairpin cotters) for Ø2 to Ø6 pins

> What size R-clip fits a given pin diameter?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: Hairpin R-clip envelopes scaled to the pin Ø: straight leg 6 × pin Ø, loop OD 3.2 × pin Ø, 1.2 wire
- Page: https://xemstudio.com/objects/r-clips/ · JSON: https://xemstudio.com/api/geometry?object=r-clips · Plain text: https://xemstudio.com/objects/r-clips/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- A hairpin clip: one straight leg goes through the pin's cross-hole and the curved leg wraps over the pin to hold it. All four files have a 1.2 mm wire, drawn flat (1.2 thick).
- Overall length and loop OD: r-clip-2 14.2 × 6.4; r-clip-3 21.3 × 9.6; r-clip-4 28.4 × 12.8; r-clip-5 35.5 × 16.0. The number in the file name is the smallest pin Ø it is drawn for; each covers that Ø and the next millimetre up.
- The 1.2 wire passes cross-holes of Ø1.2 and larger: the Ø5, Ø6 and Ø8 clevis pins (Ø1.2, Ø1.6, Ø2.0 holes).

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| R-clip wire | Ø0.8 / 1.0 / 1.2 / 1.6 / 2.0 | split-pin hole of the Ø3 / 4 / 5 / 6 / 8 clevis pin | slide | r-clip-* |

## Sizes

| file | pin Ø | wire Ø | length | loop OD |
|---|---|---|---|---|
| r-clip-3 | 2–3 | 1.2 | 14.2 | 6.4 |
| r-clip-3 | 3–4 | 1.2 | 21.3 | 9.6 |
| r-clip-4 | 4–5 | 1.2 | 28.4 | 12.8 |
| r-clip-5 | 5–6 | 1.2 | 35.5 | 16.0 |

## Where the files are

- Wikipedia: [Clevis fastener](https://en.wikipedia.org/wiki/Clevis_fastener) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Universal joint](https://en.wikipedia.org/wiki/Universal_joint) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Rod end bearing](https://en.wikipedia.org/wiki/Rod_end_bearing) — web — CC BY-SA 4.0 (text)
- McMaster-Carr: [Clevis pins (free STEP per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/clevis-pins/) — STEP, PDF — McMaster-Carr site terms (verify at link)
- McMaster-Carr: [Rod ends (free STEP per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/ball-joint-rod-ends/) — STEP, PDF — McMaster-Carr site terms (verify at link)
- Long Earth Society: [Engine and rig builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (5 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/r-clips/index.json

- r-clip-3: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-3.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-3.stl) — R-clip (hairpin) for the Ø3 clevis pins (clevis-pin-3x12, clevis-pin-3x20): wire Ø0.8 = their split-pin hole, straight leg 18 long, bow wraps the Ø3 pin
- r-clip-4: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-4.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-4.stl) — R-clip (hairpin) for the Ø4 clevis pins (clevis-pin-4x20): wire Ø1 = their split-pin hole, straight leg 24 long, bow wraps the Ø4 pin
- r-clip-5: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-5.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-5.stl) — R-clip (hairpin) for the Ø5 clevis pins (clevis-pin-5x20, clevis-pin-5x30): wire Ø1.2 = their split-pin hole, straight leg 30 long, bow wraps the Ø5 pin
- r-clip-6: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-6.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-6.stl) — R-clip (hairpin) for the Ø6 clevis pins (clevis-pin-6x30): wire Ø1.6 = their split-pin hole, straight leg 36 long, bow wraps the Ø6 pin
- r-clip-8: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-8.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-8.stl) — R-clip (hairpin) for the Ø8 clevis pins (clevis-pin-8x40): wire Ø2 = their split-pin hole, straight leg 48 long, bow wraps the Ø8 pin

## How it fits

### Goes in or on
- [Clevis pins ISO 2341 B, Ø3 to Ø8](https://xemstudio.com/objects/clevis-pins/): 1.2 wire through the pin's cross-hole

### Connects to
- [Clevises with M3 tapped shank: Ø3, Ø5 and Ø6 pins, 5 to 12 mm gaps](https://xemstudio.com/objects/clevises/): holds the pin across the fork

## Questions

**What size R-clip for a 5 mm pin?**

r-clip-4 (Ø4–5 pins) or r-clip-5 (Ø5–6): 28.4 or 35.5 mm long, 1.2 mm wire, which passes the Ø1.2 cross-hole of an ISO 2341 Ø5 clevis pin.

**How thick is the R-clip wire?**

1.2 mm on all four files.

## Fits with

- [Clevis pins ISO 2341 B, Ø3 to Ø8](https://xemstudio.com/objects/clevis-pins/)
- [Clevises with M3 tapped shank: Ø3, Ø5 and Ø6 pins, 5 to 12 mm gaps](https://xemstudio.com/objects/clevises/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)