# Clevis pins, R-clips, cotter pins, clevises, universal joint, rod ends (heim joints)

> What size clevis pin and R-clip for a 3D printed linkage?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: ISO 2341 clevis pins, DIN 11024 R-clips, common rod-end (POS/PHS series) ball sizes; printed clevises and a universal joint sized to Ø3/Ø5 pins
- Page: https://xemstudio.com/objects/pins-clevises-and-joints/ · JSON: https://xemstudio.com/api/geometry?object=pins-clevises-and-joints · Plain text: https://xemstudio.com/objects/pins-clevises-and-joints/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

## Notes

- Clevis pin: plain shank with a head and a cross-hole; Ø3 × 12–20, Ø5 × 20–30, Ø8 × 40 cover model work. Printed hole Ø+0.2 for a pivot, Ø−0.05 press in the fixed side. R-clip (hairpin) sizes by pin: 2–3 mm pin → size 2; 4–5 → size 3–4; 6–8 → size 5. Cotter pins (split pins) Ø1.6 × 16 and Ø2 × 20 for the same holes.
- Clevis: fork with a pin across the gap; gap = link thickness + 0.4. The printed ones take an M3 pushrod in the shank. A clevis + pin + R-clip is the field-serviceable joint: no tools.
- Universal joint: two yokes and a cross spider on Ø3 pins; transmits rotation across up to 25° with velocity ripple (use two, phased, for constant velocity). Ø14 printed yokes on Ø5 shafts.
- Rod ends (heim joints): M3 (ball Ø6), M4 (Ø8), M5 (Ø10), M6 (Ø12), M8 (Ø16) threaded shank, ±13° misalignment; the envelopes here are for fit; buy the steel part (POSA/PHSA series). Male on the rod, female (PHS) takes a bolt through the ball.

## Sizes

| part | sizes | mating hole | note |
|---|---|---|---|
| clevis pin | Ø3, 4, 5, 6, 8 × 12–40 | Ø + 0.2 pivot / − 0.05 press | ISO 2341 |
| R-clip | sizes 2–5 | cross-hole Ø1–1.6 | DIN 11024 |
| cotter pin | Ø1.6 × 16, Ø2 × 20 | Ø1.8 / 2.2 | ISO 1234 |
| clevis (printed) | Ø3 pin gap 5/8, Ø5 gap 8/10, Ø6 gap 12 | M3 shank | — |
| universal joint | Ø14 yokes, Ø5 shafts | Ø3 cross pins | 25° max |
| rod end | M3–M8, ball Ø6–16 | bolt through ball | POS/PHS series |

## 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 (23 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/pins-clevises-and-joints/index.json

- clevis-pin-3x12: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-3x12.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-3x12.stl) — clevis pin Ø3 × 12 with head and cross-hole for an R-clip
- clevis-pin-3x20: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-3x20.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-3x20.stl) — clevis pin Ø3 × 20 with head and cross-hole for an R-clip
- clevis-pin-4x20: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-4x20.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-4x20.stl) — clevis pin Ø4 × 20 with head and cross-hole for an R-clip
- clevis-pin-5x20: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-5x20.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-5x20.stl) — clevis pin Ø5 × 20 with head and cross-hole for an R-clip
- clevis-pin-5x30: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-5x30.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-5x30.stl) — clevis pin Ø5 × 30 with head and cross-hole for an R-clip
- clevis-pin-6x30: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-6x30.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-6x30.stl) — clevis pin Ø6 × 30 with head and cross-hole for an R-clip
- clevis-pin-8x40: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-8x40.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-pin-8x40.stl) — clevis pin Ø8 × 40 with head and cross-hole for an R-clip
- r-clip-2: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-2.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/r-clip-2.stl) — R-clip (hairpin cotter) for a Ø2–3 pin
- 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 cotter) for a Ø3–4 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 cotter) for a Ø4–5 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 cotter) for a Ø5–6 pin
- clevis-3-gap5: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-3-gap5.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-3-gap5.stl) — printed clevis for a Ø3 pin, 5 mm gap, M3 rod
- clevis-3-gap8: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-3-gap8.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-3-gap8.stl) — printed clevis for a Ø3 pin, 8 mm gap, M3 rod
- clevis-5-gap8: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-5-gap8.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-5-gap8.stl) — printed clevis for a Ø5 pin, 8 mm gap, M3 rod
- clevis-5-gap10: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-5-gap10.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-5-gap10.stl) — printed clevis for a Ø5 pin, 10 mm gap, M3 rod
- clevis-6-gap12: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-6-gap12.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/clevis-6-gap12.stl) — printed clevis for a Ø6 pin, 12 mm gap, M3 rod
- ujoint-yoke-5mm: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/ujoint-yoke-5mm.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/ujoint-yoke-5mm.stl) — universal joint yoke Ø14, Ø5 bore, Ø3 cross pins (print two)
- ujoint-spider-14: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/ujoint-spider-14.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/ujoint-spider-14.stl) — universal joint spider for the Ø14 yokes, Ø3 pins
- rod-end-m3: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m3.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m3.stl) — rod end (heim joint) envelope M3: ball bore 3, ball Ø6, head OD +4
- rod-end-m4: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m4.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m4.stl) — rod end (heim joint) envelope M4: ball bore 4, ball Ø8, head OD +4
- rod-end-m5: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m5.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m5.stl) — rod end (heim joint) envelope M5: ball bore 5, ball Ø10, head OD +4
- rod-end-m6: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m6.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m6.stl) — rod end (heim joint) envelope M6: ball bore 6, ball Ø12, head OD +4
- rod-end-m8: [STEP](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m8.step) · [STL](https://xemstudio.com/files/hardware/pins-clevises-and-joints/rod-end-m8.stl) — rod end (heim joint) envelope M8: ball bore 8, ball Ø16, head OD +4

## Questions

**What clevis pin size for a model linkage?**

Ø3 mm pins (with size-2 R-clips) for printed links up to 10 mm thick; Ø5 for anything carrying a flywheel load. Pivot holes at Ø3.2 / Ø5.2.

**What are M5 rod end dimensions?**

Ball bore 5 mm, ball Ø10, head about Ø14 × 8 mm thick, M5 shank 20 mm; ±13° of misalignment.

**How much angle can a universal joint take?**

Single joint: 25° with speed ripple; two joints with parallel yokes cancel the ripple (constant velocity) at the same angle.

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