# Split probe clamps for Ø3, Ø4.8, Ø6 probes and Ø8 / Ø9.53 dial-indicator stems

> What are DS18B20 waterproof probe and K-type thermocouple probe dimensions?

- Category: Stirling engines › Generators & instruments
- Kind: Hardware
- Basis: Common probe sizes: DS18B20 sleeve Ø6 × 50, K-type sheathed Ø3 / Ø4.8 (3/16 in); dial-indicator stems Ø8 (metric) / Ø9.53 (3/8 in); M3 pinch at ISO 273 clearance
- Page: https://xemstudio.com/objects/probe-clamps/ · JSON: https://xemstudio.com/api/geometry?object=probe-clamps · Plain text: https://xemstudio.com/objects/probe-clamps/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

- Each clamp is a 20 mm tall block, (bore + 10) × (bore + 12), with the bore at the probe or stem diameter exactly, a 1.2 mm pinch split from the bore to one edge, and a Ø3.4 (M3 clearance) pinch-screw hole crossing the split 3.5 mm outside the bore.
- DS18B20 waterproof probes have a Ø6 × 50 mm sleeve (a 30 mm version exists) and read −55 to 125 °C, so they belong on the cold side.
- K-type sheathed probes are Ø3 or Ø4.8 (3/16 in) × 100–150 mm and read to about 1100 °C; bare-bead K-type (0.3–1 mm wire) goes to about 1000 °C.
- Dial-indicator stems are Ø8 mm (metric) or Ø9.53 mm (3/8 in); I clamp one on the displacer rod to measure stroke while turning the engine by hand.

## 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 |
|---|---|---|---|---|
| probe bore | Ø6 / Ø3 / Ø4.8 / Ø8 / Ø9.53 | probe sheath or indicator stem | clamp | probe-clamp-* |
| pinch split | 1.2 | closes on the probe | clamp | probe-clamp-* |
| pinch screw hole | Ø3.4 | M3 screw clearance | designed | probe-clamp-* |

## Sizes

| clamp | bore_mm | body_mm | for |
|---|---|---|---|
| probe-clamp-k-type-3mm | 3 | 13 × 15 × 20 | K-type Ø3 |
| probe-clamp-k-type-4-8mm | 4.8 | 14.8 × 16.8 × 20 | K-type 3/16 in |
| probe-clamp-ds18b20-6mm | 6 | 16 × 18 × 20 | DS18B20 sleeve |
| probe-clamp-dial-indicator-8mm | 8 | 18 × 20 × 20 | metric indicator stem |
| probe-clamp-dial-indicator-3-8in | 9.53 | 19.53 × 21.53 × 20 | 3/8 in indicator stem |

## Where the files are

- Wikipedia: [Thermocouple](https://en.wikipedia.org/wiki/Thermocouple) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Hall effect sensor](https://en.wikipedia.org/wiki/Hall_effect_sensor) — web — CC BY-SA 4.0 (text)
- Wikipedia: [Dial indicator](https://en.wikipedia.org/wiki/Dial_indicator) — web — CC BY-SA 4.0 (text)
- Analog Devices: [DS18B20 datasheet](https://www.analog.com/en/products/ds18b20.html) — PDF — Manufacturer datasheet
- 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/probe-clamps/index.json

- probe-clamp-ds18b20-6mm: [STEP](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-ds18b20-6mm.step) · [STL](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-ds18b20-6mm.stl) — split clamp for a Ø6 probe/stem (ds18b20 6mm): Ø6 bore, 1.2 mm split, M3 pinch (Ø3.4)
- probe-clamp-k-type-3mm: [STEP](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-k-type-3mm.step) · [STL](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-k-type-3mm.stl) — split clamp for a Ø3 probe/stem (k type 3mm): Ø3 bore, 1.2 mm split, M3 pinch (Ø3.4)
- probe-clamp-k-type-4-8mm: [STEP](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-k-type-4-8mm.step) · [STL](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-k-type-4-8mm.stl) — split clamp for a Ø4.8 probe/stem (k type 4 8mm): Ø4.8 bore, 1.2 mm split, M3 pinch (Ø3.4)
- probe-clamp-dial-indicator-8mm: [STEP](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-dial-indicator-8mm.step) · [STL](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-dial-indicator-8mm.stl) — split clamp for a Ø8 probe/stem (dial indicator 8mm): Ø8 bore, 1.2 mm split, M3 pinch (Ø3.4)
- probe-clamp-dial-indicator-3-8in: [STEP](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-dial-indicator-3-8in.step) · [STL](https://xemstudio.com/files/hardware/instrument-mounts/probe-clamp-dial-indicator-3-8in.stl) — split clamp for a Ø9.53 probe/stem (dial indicator 3 8in): Ø9.53 bore, 1.2 mm split, M3 pinch (Ø3.4)

## How it fits

### Goes in or on
- [Tri-clamp (Tri-Clover) sanitary ferrule, 1/2 to 4 inch](https://xemstudio.com/objects/tri-clamp-ferrule/): K-type at the hot end, DS18B20 on the cold spool

### Connects to
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/): M3 pinch screw through the Ø3.4 hole

### Also needed
- [Hall sensor mount for TO-92S (A3144 / SS49E)](https://xemstudio.com/objects/hall-sensor-mount/): RPM alongside temperature

## Questions

**What are the dimensions of a DS18B20 waterproof probe?**

A Ø6 mm sleeve, 50 mm long (30 mm versions exist); it reads to 125 °C.

**What diameter are K-type thermocouple probes?**

Sheathed probes are Ø3 or Ø4.8 mm (3/16 in), 100–150 mm long.

**What diameter is a dial indicator stem?**

8 mm on metric indicators, 9.53 mm (3/8 in) on US ones.

## Fits with

- [Hall sensor mount for TO-92S (A3144 / SS49E)](https://xemstudio.com/objects/hall-sensor-mount/)
- [Optical encoder disc Ø60, 30 slots, Ø5 bore](https://xemstudio.com/objects/encoder-disc/)
- [Tri-clamp (Tri-Clover) sanitary ferrule, 1/2 to 4 inch](https://xemstudio.com/objects/tri-clamp-ferrule/)
- [Thermoelectric (Peltier) modules: TEC1-12706, 12710, 30 mm](https://xemstudio.com/objects/thermoelectric-tec1/)
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)