# Tri-clamp racking arm: 1½ in clamp body and ½ in arms, 2 to 6 in reach

> What is a tri-clamp racking arm?

- Category: Hardware › Sanitary clamp fittings
- Kind: Hardware
- Basis: Xem Studio design: a 1½ in clamp body with a sealed bore for ½ in tube (two O-rings), and a bent arm that turns inside the vessel
- Page: https://xemstudio.com/objects/tri-clamp-racking-arms/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-racking-arms · Plain text: https://xemstudio.com/objects/tri-clamp-racking-arms/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Turn the arm down to draw from the bottom, up to rack clear beer off the yeast. Fits a 1½ in side port on a fermenter.
- Every clamp face is the ISO 2852 profile used across this site: 2.85 mm rim, flat face with the gasket groove (K 1.6 deep, R3 1.2 bottom, 23° walls, P2 0.8 edges) on C2, 20° back cone. Flange C3 / groove C2 / tube OD × wall, mm: ½–¾ in 25.0 / 20.4 (derived) / 12.7–19.05 × 1.65; 1–1½ in 50.5 / 43.5 / 25.4–38.1 × 1.65; 2 in 64.0 / 56.5 / 50.8 × 1.65; 2½ in 77.5 / 70.5 / 63.5 × 1.65; 3 in 91.0 / 83.5 / 76.2 × 1.65; 4 in 119.0 / 110.0 / 101.6 × 2.11; 6 in 166.9 (6.570 in) / 156.5 / 152.4 × 2.77; 8 in 217.7 (8.570 in) / 207.0 / 203.2 × 2.77; 10 in 268.5 / 261.0 / 254.0 × 3.40; 12 in 319.3 / 311.8 / 304.8 × 3.40.

## Sizes

| reach_in | reach_mm | tube_od_mm | o_rings |
|---|---|---|---|
| 2 | 50.8 | 12.7 | AS568-012 × 2 |
| 4 | 101.6 | 12.7 | AS568-012 × 2 |
| 6 | 152.4 | 12.7 | AS568-012 × 2 |

## Where the files are

- GW Kent: [Tri-clamp fittings guide: tube OD, flange OD and ID per size to 12 in; solid cap thickness](https://www.gwkent.com/triclamp-guide) — web — publisher's guide; dimensions cited
- Rubber Fab: [Tri-Clamp gasket dimensional chart: gasket ID, OD and bead diameter per size (2 in bead 2.22 in / 56.50 mm, 1.5 in 1.71 / 43.50, 3 in 3.29 / 83.50)](https://shop.andersonprocess.com/media/assets/product/documents/rubber-fab-tri-clamp-dimensions.pdf) — PDF — maker chart; dimensions are facts (verify at link)

## Free STEP/STL (4 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/tri-clamp-racking-arms/index.json

- racking-arm-body-1.5in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-body-1.5in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-body-1.5in.stl) — 1½ in clamp body: Ø24 boss 40 long, Ø12.8 bore with two AS568-012 O-ring grooves for ½ in tube
- racking-arm-tube-2in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-2in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-2in.stl) — ½ in (Ø12.7 × 1.6) arm: 60 straight through the body, 90° bend on R25, 2 in reach
- racking-arm-tube-4in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-4in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-4in.stl) — ½ in (Ø12.7 × 1.6) arm: 60 straight through the body, 90° bend on R25, 4 in reach
- racking-arm-tube-6in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-6in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-racking-arms/racking-arm-tube-6in.stl) — ½ in (Ø12.7 × 1.6) arm: 60 straight through the body, 90° bend on R25, 6 in reach

## Questions

**What seals the arm?**

Two AS568-012 O-rings in the body bore; the arm turns in them.

## Fits with

- [Tri-clamp dip-tube caps: 1½ and 2 in, ⅜ in tube 6 to 24 in long](https://xemstudio.com/objects/tri-clamp-dip-tube-caps/)
- [Tri-clamp vessels with a dished or round welded bottom: 4, 6 and 8 in, 12 to 24 in deep](https://xemstudio.com/objects/tri-clamp-dished-bottom-vessels/)
- [Tri-clamp butterfly valves, printable: 1½ to 4 in](https://xemstudio.com/objects/tri-clamp-butterfly-valves/)