# Mutilated bevel gear driving two bevel gears alternately, opposite ways

> How does a half-toothed bevel gear drive two gears in turn?

- Category: Mechanisms › Intermittent motion
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 74 (1868)
- Page: https://xemstudio.com/objects/mutilated-bevel-gear-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=mutilated-bevel-gear-mechanism · Plain text: https://xemstudio.com/objects/mutilated-bevel-gear-mechanism/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- 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

- A bevel gear with teeth on only half its rim turns continuously between two bevel gears facing each other: for half a turn its teeth drive one, for the other half the other. The two driven gears face opposite ways, so they turn in opposite directions, each moving half a turn and then resting.
- Three module 2, 20-tooth spherical-involute mitre gears (one with 10 teeth cut away), cone distance 28.28 mm; drawn with the toothed half in mesh with gear A, gear B free.
- Brown's No. 74. The driven gears here turn on separate stub shafts so each can rest independently.
- Parts (each has its own page): mitre-gear-m2-20t-bore5-half-teeth, mitre-gear-m2-20t-bore5, dowel-pins-metric.
- Brown's movement No. 74 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| driver | mitre, 10 of 20 teeth |
| driven | 2 × mitre 20 T |
| each driven gear | half a turn, then rest |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 74: figure, his text and an animation](https://507movements.com/mm_074.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/mutilated-bevel-gear-mechanism/index.json · license: https://xemstudio.com/files/hardware/mutilated-bevel-gear-mechanism/LICENSE.md

- mutilated-bevel-gear-mechanism-assembly: [STEP](https://xemstudio.com/files/hardware/mutilated-bevel-gear-mechanism/mutilated-bevel-gear-mechanism-assembly.step) · [STL](https://xemstudio.com/files/hardware/mutilated-bevel-gear-mechanism/mutilated-bevel-gear-mechanism-assembly.stl) — Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)

## Questions

**How does a half-toothed bevel gear drive two gears in turn?**

A bevel gear with teeth on only half its rim turns continuously between two bevel gears facing each other: for half a turn its teeth drive one, for the other half the other. The two driven gears face opposite ways, so they turn in opposite directions, each moving half a turn and then resting.

## Fits with

- [Mutilated mitre gear, module 2, 20 teeth with 10 kept (half), Ø5 bore](https://xemstudio.com/objects/mitre-gear-m2-20t-bore5-half-teeth/)
- [Mitre (bevel) gear, module 2, 20 teeth, Ø5 bore, spherical involute](https://xemstudio.com/objects/mitre-gear-m2-20t-bore5/)
- [Dowel pins, 2–6 mm (ISO 2338 / DIN 6325)](https://xemstudio.com/objects/dowel-pins-metric/)