# Pololu 20D 100:1 metal gearmotor 6 V (#3454): body, Ø4 shaft and M2.5 face-plate holes

> What are the Pololu 20D 100:1 6 V gearmotor dimensions and face-plate mounting holes?

- Category: Electronic components › Motors
- Kind: Modern device
- Basis: Pololu product page #3454 and the Pololu '20D mm Metal Gearmotors' dimension drawing; hole spacing cross-checked with the Pololu 20D bracket #1138 drawing.
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- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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## Overall (mm)

| length | width | height |
|---|---|---|
| 62.1 | 20.0 | 20.0 |

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Datum: motor axis along z, rear of the motor can at 0, output shaft toward +z.
- Motor can Ø20.0 × 25.1; gearbox Ø20.0 × 19.0 (L for 100:1), face plate at 44.1 from the rear.
- Output shaft Ø4.0 D-shaft extending 18.0 from the face plate (the D-flat is not dimensioned; drawn round).
- Two M2.5 threaded holes in the face plate, 15.0 apart on a line through the shaft (±7.5); maximum screw engagement 3.5 (modelled Ø2.5 × 3.5 deep).
- Gearbox length by ratio: 16.0 (25:1, 31:1), 17.5 (63:1, 78:1), 19.0 (100:1 to 195:1), 20.5 (250:1 to 488:1); 12 V, CB and extended-shaft versions share the face plate and shaft. Not modelled: rear motor terminals.
- Dimensions are exact nominal (true size), no tolerance added.

## 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 |
|---|---|---|---|---|
| face-plate holes | 2 × M2.5, 15.0 apart, 3.5 max engagement | Pololu 20D bracket or a custom bracket, M2.5 screws | designed | all |
| output shaft | Ø4.0 D-shaft, 18.0 long | wheel hub, coupler or adapter | slide | all |
| gearbox body | Ø20.0 | clamp-style motor mount | clamp | all |

## Sizes

| feature | x (mm) | y (mm) | size |
|---|---|---|---|
| face-plate hole 1 | −7.5 | 0 | M2.5, 3.5 max engagement |
| face-plate hole 2 | +7.5 | 0 | M2.5, 3.5 max engagement |
| output shaft | 0 | 0 | Ø4.0 D, 18.0 long |

## Where the files are

- Pololu: [100:1 Metal Gearmotor 20Dx44L mm 6V (#3454)](https://www.pololu.com/product/3454) — web — Publisher's page; dimensions are facts
- Pololu: [20D mm Metal Gearmotors dimension drawing](https://www.pololu.com/file/0J1242/20d-metal-gearmotor-dimension-diagram.pdf) — web — Publisher's page; dimensions are facts
- Pololu: [20D gearmotor bracket #1138 dimensions](https://pololu.com/file/0J724/1138-bracket-dimensions.pdf) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/pololu-20d-metal-gearmotor-100-1-6v/index.json

- pololu-20d-metal-gearmotor-100-1-6v: [STEP](https://xemstudio.com/files/hardware/pololu-20d-metal-gearmotor-100-1-6v/pololu-20d-metal-gearmotor-100-1-6v.step) · [STL](https://xemstudio.com/files/hardware/pololu-20d-metal-gearmotor-100-1-6v/pololu-20d-metal-gearmotor-100-1-6v.stl) — Pololu 20D 100:1 metal gearmotor 6 V (#3454): body, Ø4 shaft and M2.5 face-plate holes

## Questions

**What are the Pololu 20D face-plate holes?**

Two M2.5 threaded holes 15.0 mm apart on a line through the shaft; use at most 3.5 mm of screw engagement.

**How long is the 20D 100:1 gearmotor?**

44.1 mm body (25.1 mm motor + 19.0 mm gearbox), Ø20 mm, plus an 18 mm Ø4 mm D-shaft: 62.1 mm overall.

## Fits with

- [775 brushed DC motor Ø42 × 66.7 mm, Ø5 shaft](https://xemstudio.com/objects/775-dc-motor/)
- [JGA25-370 gearmotor: Ø25 gearbox on a 370 can, Ø4 D-shaft](https://xemstudio.com/objects/jga25-370-gearmotor/)
- [Flexible shaft couplers, 5–10 mm bores](https://xemstudio.com/objects/shaft-couplers/)
- [Metric shafts Ø3 to Ø10 with D-flats and clip grooves](https://xemstudio.com/objects/metric-shafts/)
- [Metric machine screws M1.6–M10: pan head ISO 7045 (cross) / ISO 1580 (slotted), cheese head ISO 1207, countersunk ISO 7046-1 — head sizes, recess sizes + models](https://xemstudio.com/objects/machine-screws-metric-pan-cheese-csk/)