# Mug LTD bottom plate Ø90 × 6 (sits on an 11 oz mug)

> What size plate does a Stirling engine need to sit on a coffee mug?

- Category: Hardware › Stirling & thermoacoustic
- Kind: Hardware
- Basis: Ø90 chosen to sit on an 11 oz mug (rim Ø82.55 = 3.25 in, listing cited) with 3.7 mm overhang; proportions scaled from the LTD kit
- Page: https://xemstudio.com/objects/mug-ltd-bottom-plate/ · JSON: https://xemstudio.com/api/geometry?object=mug-ltd-bottom-plate · Plain text: https://xemstudio.com/objects/mug-ltd-bottom-plate/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

- Ø90 × 6 hot plate. The 11 oz mug's rim is Ø82.55 (3.25 in); the plate overhangs it by 3.7 mm all round and its underside is flat: the chamber screws go into M3 tapped holes (Ø2.5 tap drill, through) and stop 2 mm above the underside, so nothing stands proud where the plate rests on the rim.
- 5 × M3 tapped on R41 at 60°, 120°, 180°, 240° and 300° (0° is under the syringe socket); the chamber ring and the top plate stack on it (ring 23, top plate 3) and five M3 × 30 from the top plate reach 4 mm into it.

## 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 |
|---|---|---|---|---|
| chamber screw holes | Ø2.5 (M3 tapped), 5 on R41 | shcs-m3x30 | designed | all |
| underside on the mug rim | Ø90 flat on an Ø82.55 rim | 11 oz mug (found object) | designed | all |

## Sizes

| feature | size_mm |
|---|---|
| plate | Ø90 × 6 |
| screw circle | R41, 5 × M3 tapped Ø2.5 |
| mug rim (11 oz) | Ø82.55 |

## Where the files are

- Atlanta Vinyl Store: [Premium 11 oz sublimation mug: 3.75 in H × 3.25 in D](https://atlantavinylstore.com/products/premium-11oz-sublimation-mugs) — web — listing (verify at link)
- James R. Senft: [An Introduction to Low Temperature Differential Stirling Engines](https://www.stirlingengine.com/) — book — Moriya Press (verify at link)
- Wikipedia: [Stirling engine](https://en.wikipedia.org/wiki/Stirling_engine) — web — CC BY-SA 4.0 (text)
- 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/mug-ltd-bottom-plate/index.json

- mug-ltd-bottom-plate-90: [STEP](https://xemstudio.com/files/hardware/mug-ltd-bottom-plate/mug-ltd-bottom-plate-90.step) · [STL](https://xemstudio.com/files/hardware/mug-ltd-bottom-plate/mug-ltd-bottom-plate-90.stl) — bottom (hot) plate Ø90 × 6, 5 × M3 tapped (Ø2.5) through on R41 at 60°, 120°, 180°, 240°, 300°; rests on an 11 oz mug rim (Ø82.55)

## Questions

**Will a Ø90 plate sit on a coffee mug?**

On an 11 oz mug (rim Ø82.55) yes, with 3.7 mm overhang; 15 oz mugs are wider, so measure yours.

## Fits with

- [Build list: Mug LTD (sits on a coffee mug)](https://xemstudio.com/objects/list-ltd-mug/)
- [LTD Stirling bottom plate, Ø120 and Ø170](https://xemstudio.com/objects/ltd-bottom-plate/)
- [LTD Stirling top plate with syringe socket, Ø120 and Ø170](https://xemstudio.com/objects/ltd-top-plate/)
- [Glass syringes 1–50 mL (all-glass, ground-glass plunger): barrel and plunger](https://xemstudio.com/objects/glass-syringes/)