# Reversing-groove drum Ø30 × 90: crossed right- and left-hand grooves, pitch 30, 5 wide

> What is a reversing screw drum?

- Category: Hardware › Mechanism parts
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/reversing-groove-drum-30x90-p30/ · JSON: https://xemstudio.com/api/geometry?object=reversing-groove-drum-30x90-p30 · Plain text: https://xemstudio.com/objects/reversing-groove-drum-30x90-p30/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/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 30.0 | 30.0 | 90.0 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Ø30 × 90 cylinder (Ø5 bore) with two 5 mm wide, 3 mm deep grooves cut over the middle 60 mm: one right-hand and one left-hand helix of 30 mm pitch (two turns each), crossing each other at 180° and meeting at 0°. Each groove is 5 mm wide measured square to its path at the bottom (5.38 mm axially; helicoid flanks, 0.17 mm wider at the surface). A Ø5 pin in the groove runs 60 mm up in two turns of the drum, turns the corner and runs 60 mm back in the next two.
- The level-wind (fishing reel, winch) drum: the turn-around is drawn as the sharp meeting of the two helices; a real traverser carries a keel-shaped shoe that is steered round it.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| drum | Ø30 × 90 mm |
| grooves | RH + LH, pitch 30, 2 turns each |
| groove | 5 wide × 3 deep |
| traverse | 60 mm per 2 turns |
| bore | Ø5 |

## 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. 108: figure, his text and an animation](https://507movements.com/mm_108.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/reversing-screw-traverse-mechanism/) — web — Publisher's page; dimensions are facts

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

Index: https://xemstudio.com/files/hardware/reversing-groove-drum-30x90-p30/index.json · license: https://xemstudio.com/files/hardware/reversing-groove-drum-30x90-p30/LICENSE.md

- reversing-groove-drum-30x90: [STEP](https://xemstudio.com/files/hardware/reversing-groove-drum-30x90-p30/reversing-groove-drum-30x90.step) · [STL](https://xemstudio.com/files/hardware/reversing-groove-drum-30x90-p30/reversing-groove-drum-30x90.stl) — drum, axis Z, grooves z 15..75, both start at angle 0

## Questions

**What is a reversing screw drum?**

Ø30 × 90 cylinder (Ø5 bore) with two 5 mm wide, 3 mm deep grooves cut over the middle 60 mm: one right-hand and one left-hand helix of 30 mm pitch (two turns each), crossing each other at 180° and meeting at 0°. Each groove is 5 mm wide measured square to its path at the bottom (5.38 mm axially; helicoid flanks, 0.17 mm wider at the surface). A Ø5 pin in the groove runs 60 mm up in two turns of the drum, turns the corner and runs 60 mm back in the next two.

## Fits with

- [Reversing-screw drum and traverser (uniform to-and-fro traverse)](https://xemstudio.com/objects/reversing-screw-traverse-mechanism/)