# Motor-mount plate for a 2 in tri-clamp cross: clamps between two faces, holds a 2208 gimbal motor inside

> How do I mount a motor inside a sealed tri-clamp vessel?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: ISO 2852 face and 20° back on both sides as the clamp-in bearing plate on this site (16 mm face to face for two standard clamps); motor base holes (4-M3 on 19 × 16) from the 2208 listing; ISO 273 medium clearance for M3 and ISO 10642 countersink (90°, Ø6)
- Page: https://xemstudio.com/objects/tri-clamp-motor-mount-plate/ · JSON: https://xemstudio.com/api/geometry?object=tri-clamp-motor-mount-plate · Plain text: https://xemstudio.com/objects/tri-clamp-motor-mount-plate/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.** 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 ring clamped between the cross's top face and the port cap, like a thick gasket, each side its own Type B gasket and clamp. Its Ø30 bore lets the gas and the motor's three leads through to the port cap.
- From the ring a column hangs down the cross's top run to a mount face 62.1 mm below the plate. The motor's base bolts to it with four M3 × 6 countersunk screws whose heads sit flush, because the top run leaves no room for heads behind the face. The holes follow the motor's 16 and 19 mm pairs, turned 45° so the face stays inside the Ø47.5 bore.
- Everything stays inside the bore and inside the gasket lip (Ø45.3) where it passes the joint. The motor hangs over the crank, its axis parallel to the crankshaft, its pinion in mesh with the crank gear.

## 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 |
|---|---|---|---|---|
| faces | ISO 2852 both sides (land Ø56.5–Ø64, rim 2.85, 1.6 recess, 20° back to Ø50.8) | standard clamps + Type B gaskets | clamp | all |
| mount face holes | 4 × Ø3.4, 90° countersink Ø6, 16 / 19 pattern turned 45° | csk-m3x6 into the motor base | designed | all |
| mount face | flat, x 15 from the cross axis | 2208 motor base | designed | all |
| bore | Ø30 | gas and the motor leads to the port cap | designed | all |

## Sizes

| feature | value |
|---|---|
| faces | ISO 2852 both sides, 2 in |
| face to face | 16.0 |
| bore | Ø30 |
| column | x 6–21, |y| ≤ 7 |
| mount face | 3 thick, |y| ≤ 12, 4 × Ø3.4 csk Ø6 × 90° |
| motor axis below the inner face | 62.1 |

## Where the files are

- ISO (via iTeh sample): [ISO 2852 clamp liners: face profile and flange / groove diameters](https://cdn.standards.iteh.ai/samples/7850/eb49c396488d408c8ced3e2961d76cf3/ISO-2852-1974.pdf) — PDF — standard excerpt; dimensions are facts
- ASME: [BPE Bioprocessing Equipment (clamp fitting dimensions, tube OD and wall)](https://www.asme.org/codes-standards/find-codes-standards/bpe-bioprocessing-equipment) — standard — ASME; dimensions are facts (verify at link)
- ISO: [ISO 273 clearance holes for bolts and screws (fine / medium / coarse)](https://www.iso.org/standard/4196.html) — standard — dimensions are facts (verify at link)
- GetFPV (product listing): [Tiger GB2208-80 gimbal motor: 27.5 × 23, 4.5 hollow shaft, stator 4-M3 on 19 × 16, rotor 4-M2 on 12 × 12](https://www.getfpv.com/tiger-gb2208-80-brushless-gimbal-motor-hollow-shaft.html) — web — vendor page; dimensions are facts (verify at link)
- Long Earth Society: [Engine builds](https://longearthsociety.com/engineering/) — web, video — LES site

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/tri-clamp-motor-mount-plate/index.json

- motor-mount-plate-2in-2208: [STEP](https://xemstudio.com/files/hardware/tri-clamp-motor-mount-plate/motor-mount-plate-2in-2208.step) · [STL](https://xemstudio.com/files/hardware/tri-clamp-motor-mount-plate/motor-mount-plate-2in-2208.stl) — motor-mount plate: ISO 2852 face and 20° back on both sides, 16 face to face, Ø30 bore; column x 6–21, |y| ≤ 7 hanging 47.3 below the inner face; mount face x 15–18, |y| ≤ 12, 4 × Ø3.4 countersunk 90° to Ø6 with a 0.2 rim (ISO 10642 head) on the 16 / 19 pattern turned 45°, Ø8 centre relief; motor axis 62.1 below the inner face

## Questions

**Why does the mount hang from the top joint?**

The top joint is the only face of the cross above the crank; the motor has to sit over the crank so its gear can reach the crankshaft.

## Fits with

- [2208 gimbal motor: outside envelope and mounting holes (Ø27.5 × 23, base M3 on 19 × 16, rotor M2 on 12 × 12)](https://xemstudio.com/objects/gimbal-motor-2208-envelope/)
- [Step-up gears for a generator inside a 2 in tri-clamp cross: 42 : 15, module 1](https://xemstudio.com/objects/tri-clamp-generator-step-up-gears/)
- [Clamp-in bearing plate: 2 in, two ISO 2852 faces, spigot with two 623 seats](https://xemstudio.com/objects/tri-clamp-clamp-in-bearing-plate/)
- [Tri-clamp port cap: 2 in, four 1/8 NPT ports for a fill valve, a gauge, a relief valve and an electrical pass-through](https://xemstudio.com/objects/tri-clamp-port-cap/)
- [Build list: Tri-clamp sealed diaphragm generator, 2 in](https://xemstudio.com/objects/list-tri-clamp-sealed-diaphragm-generator/)