# Tri-clamp thermowells: 1½ and 2 in clamp, 2½ to 12 in insertion, ½ NPT top

> What thermowell fits a 1½ inch tri-clamp port?

- Category: Hardware › Sanitary clamp fittings
- Kind: Hardware
- Basis: Xem Studio design: the standard solid cap with a ⅜ in (9.53) well closed by a round tip, a Ø6.6 bore for a ¼ in (6.35) thermometer or probe stem, and a ½ NPT Class 3000 half coupling on top (tap-drill bore)
- Page: https://xemstudio.com/objects/tri-clamp-thermowells/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-thermowells · Plain text: https://xemstudio.com/objects/tri-clamp-thermowells/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

- The temperature stick: clamp it into a port and slide a ¼ in stem thermometer or probe into the well, so the probe never touches the liquid. Insertion is measured from the clamp face to the tip.
- Pick the length so the tip sits in the middle of the liquid: in a 6 in × 18 in vessel through the top, 12 in; through a side port, 2½ to 4 in.
- 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

| clamp | insertion_in | insertion_mm | well_od_mm | bore_mm |
|---|---|---|---|---|
| 1–1½ | 2.5 | 63.5 | 9.53 | 6.6 |
| 1–1½ | 4 | 101.6 | 9.53 | 6.6 |
| 1–1½ | 6 | 152.4 | 9.53 | 6.6 |
| 1–1½ | 9 | 228.6 | 9.53 | 6.6 |
| 1–1½ | 12 | 304.8 | 9.53 | 6.6 |
| 2 | 2.5 | 63.5 | 9.53 | 6.6 |
| 2 | 4 | 101.6 | 9.53 | 6.6 |
| 2 | 6 | 152.4 | 9.53 | 6.6 |
| 2 | 9 | 228.6 | 9.53 | 6.6 |
| 2 | 12 | 304.8 | 9.53 | 6.6 |

## Where the files are

- ASME: [B1.20.1 Pipe threads, general purpose (NPT): major diameter, L2, tap drill; B16.11 forged fittings (Class 3000 couplings); B36.10 Sch 40 bore](https://www.asme.org/codes-standards/find-codes-standards/b1-20-1-pipe-threads-general-purpose-inch) — standard — ASME; dimensions are facts (verify at link)
- 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 (10 parts, CC BY 4.0, Xem Studio)

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

- thermowell-1.5in-2.5in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-2.5in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-2.5in.stl) — 1–1½ in clamp thermowell, 2.5 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-1.5in-4in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-4in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-4in.stl) — 1–1½ in clamp thermowell, 4 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-1.5in-6in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-6in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-6in.stl) — 1–1½ in clamp thermowell, 6 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-1.5in-9in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-9in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-9in.stl) — 1–1½ in clamp thermowell, 9 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-1.5in-12in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-12in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-1.5in-12in.stl) — 1–1½ in clamp thermowell, 12 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-2in-2.5in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-2.5in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-2.5in.stl) — 2 in clamp thermowell, 2.5 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-2in-4in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-4in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-4in.stl) — 2 in clamp thermowell, 4 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-2in-6in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-6in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-6in.stl) — 2 in clamp thermowell, 6 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-2in-9in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-9in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-9in.stl) — 2 in clamp thermowell, 9 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top
- thermowell-2in-12in: [STEP](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-12in.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-thermowells/thermowell-2in-12in.stl) — 2 in clamp thermowell, 12 in insertion below the face: Ø9.53 well, Ø6.6 bore for a ¼ in stem, ½ FNPT on top

## Questions

**What fits in it?**

Any ¼ in (6.35 mm) stem: a bimetal dial thermometer, a thermocouple or an RTD probe.

## Fits with

- [Tri-clamp dial thermometers (envelope): 3 and 5 in dial, ¼ in stem 2½ to 12 in, 1½ in clamp](https://xemstudio.com/objects/tri-clamp-dial-thermometers/)
- [Tri-clamp end caps with ports: NPT, clamp nozzle, hose barb and airlock hole, 1½ to 8 in](https://xemstudio.com/objects/tri-clamp-ported-end-caps/)
- [Tri-clamp dome lids: 1½ to 12 in, plain or with a port at the crown](https://xemstudio.com/objects/tri-clamp-dome-lids/)
- [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/)