# Cotton gin

> Pulling the fibre off the seed

- Date: c. 500
- Era: Middle Ages
- Domain: [Tools & Making](https://lastcodex.org/en/domains/tools/)
- Rebuild stage: III (Crafts & cities)
- Difficulty: 2/5
- URL: https://lastcodex.org/en/inventions/cotton-gin/

A cotton gin separates cotton fibre from the seeds it grows on. Roller gins pinch the fibre between turning rollers and leave the seed behind; saw gins drag it off with teeth. The oldest known gins come from India, by the fifth or sixth century CE. Eli Whitney's toothed gin, patented in 1794, made short-staple cotton profitable across the American South and raised the demand for enslaved labour there.

![Cotton gin · Pulling the fibre off the seed](https://lastcodex.org/_astro/plate.BtIus28n_qGERI.webp)

## Legend

1. Crank
2. Two wooden rollers
3. Worms that turn the rollers in opposite directions
4. Wedge pressing the rollers together
5. Seed held back at the nip
6. Fibre drawn between the rollers

## What it is

![A short cotton stem with an open boll: the dry brown casing has split into pointed segments and white locks of seed cotton bulge out of it; beside it on the ground, a single dark seed still wrapped in long white fibres](https://lastcodex.org/_astro/v3.MhlwyMWr_Z1h8bmw.webp)
_In the open boll, the fibre is still attached to the seeds it grew on._

Raw cotton, as it comes from the open boll, is a tuft of fibres still attached to the seeds they grew on. Before it can be [spun](/en/inventions/spinning-wheel/) and [woven](/en/inventions/weaving/), the fibre, called lint, has to come off. The seeds can be picked out with the fingers, but slowly, and a gin does the work mechanically. The word is probably a short form of "engine".

There are two main kinds. A roller gin grips the fibre between rollers and pulls it away, while the seed, too large to follow, stays behind. A saw gin catches the fibre on teeth and drags it through gaps too narrow for the seed. Roller gins keep the fibre long and are still used for long-staple cotton such as Pima. Saw gins work much faster and became the standard for Upland cotton, the short-staple kind that came to dominate American production.

## How it works

In the two-roller gin of India, the churka or charkhi, two thin wooden rollers lie one above the other between two uprights, wedged hard against each other. The worker holds a tuft of seed cotton against the line where they meet and turns a crank. The rollers turn in opposite directions, so at the nip both surfaces move away from the worker, catch the loose ends of the fibres and draw them through. The seed is too thick to enter. It is held at the front while its fibres are pulled from it, and once bare it drops. The lint comes out behind the rollers as a thin sheet. Rollers kept thin grip the fibre without crushing the seed.

Only one roller carries the crank. At the other end, each roller has a worm, a spiral thread cut into the wood, and the two worms mesh like a pair of [gears](/en/inventions/gear/), so turning one roller turns the other the opposite way. Other two-roller gins have no worms and a crank on each roller.

The saw gin tears instead of pinching. Seed cotton lies in a box against a grid of parallel iron ribs. Behind the ribs turns a row of circular saws whose teeth come through the gaps. The teeth catch the fibre and pull it between the ribs, where the seed cannot follow, and a brush cylinder behind the saws strips the lint off the teeth. The bare seed falls out through an opening at the bottom of the box. The teeth work fast but break some of the fibres.

Upland cotton is harder to gin than long-staple cotton. Its seeds keep a coat of short fuzz after ginning, and its fibres hold to the seed more firmly than those of Pima.

## How to do it

A hand model shows how a roller gin works without any real machinery. You need raw cotton with its seeds, sold for hand spinners or picked from a cotton plant, a smooth board, and a smooth steel rod or hardwood dowel about 1 cm thick. For the second model, take two hardwood dowels 12 mm thick and 30 cm long, a board about 22 by 12 cm, two pieces of wood 12 cm long and about 4 by 2 cm in section, a short wooden arm for the crank, glue, two small screws, two strong rubber bands and an ice-lolly stick.

**Roll the seeds out.** Spread a small tuft of seed cotton on the board. Hold the rod by both ends and roll it slowly over the tuft and back, pressing down. The rod flattens the fibre against the board and squeezes the seeds out towards the edge of the tuft. Press too hard and the seeds break into the fibre; too lightly and they stay caught. Pick out the freed seeds and roll again.

**Make the frame.** Cut a slot 13 mm wide and about 4 cm deep into the top of each upright. Glue the uprights at the two ends of the board, broad faces towards each other, so that a dowel laid across rests in both slots with its ends sticking out by a few centimetres. Lay one dowel in the slots, then the other on top of it. Drive a small screw into the outer face of each upright near the bottom, and stretch a rubber band from each screw over the projecting end of the upper dowel, so that it presses down on the lower one.

**Fit the crank.** Drill a 12 mm hole near one end of the wooden arm and a smaller one near the other end. Glue the arm onto the very end of the lower dowel, clear of the rubber band, and a short peg into the small hole as a handle. When you turn the crank, the lower roller should drive the upper one the opposite way by friction. If it slips, wrap both dowels along their working length with one layer of cloth tape.

**Gin.** Turn the crank slowly so that the top of the lower roller moves away from you. Tease a few fibres loose from a tuft of seed cotton, lay their ends on the nip and push the tuft against the rollers with the ice-lolly stick. The rollers draw the fibre through to the back, and the seeds stay in front and fall when they are clean.

**Safety.** The nip where the rollers meet can catch a fingertip, hair or a loose sleeve. Feed the cotton only with the stick, keep your fingers well back from the rollers, tie back long hair and turn the crank only by hand: never drive the rollers with a drill or a motor. An adult should do the sawing and drilling, with the work clamped. Cotton seeds are not food; keep them away from small children and pets.

## History and evolution

![A thin rod held at both ends by two hands and rolled over a tuft of seed cotton on a flat stone, with freed seeds beside it](https://lastcodex.org/_astro/v1.KnPM-bYv_Z1e40iv.webp)
_The single-roller gin: a rod rolled on a flat stone presses the seeds out of the fibre._

The oldest gin needed no frame. A roller of iron or hardwood, no more than about 1.6 cm thick, was rolled over seed cotton on a flat stone or board, like a rolling pin. In a history of the gin, engineers of the US Department of Agriculture, following the historian Angela Lakwete, write that this single-roller gin existed by the fifth century CE and probably much earlier, though two loose parts are hard to recognise in an excavation. It has survived for traditional uses, and the same authors watched a woman gin cotton with one in Mali in 2007.

Irfan Habib, a historian of Indian technology, places a geared gin in the same period. A wall painting in Cave I at Ajanta, in western India, shows a scene of cotton working that Dieter Schlingloff had read as a bow for beating fibre. Following Ishrat Alam, Habib identifies the frame in it as a gin with thin rollers and dates the painting to about 600. In his reading the rollers were already coupled by worms, but there was no crank and the upper roller was turned by hand. Joseph Needham had argued that the worm gin began in India and reached China twice, through Burma and Indochina in about the fifth century and through Central Asia in the thirteenth. In China it lost its worms and was given two cranks, or a crank and a treadle. Habib finds no Indian picture of a crank earlier than the seventeenth century.

Two-roller gins of the churka type were used for centuries in India, China, South-East Asia and the Middle East, worked by hand or by foot, and they reached the Caribbean with cotton growing. They were in use in North America by 1750. Mechanics enlarged them for plantations: in 1788 Joseph Eve of Augusta, Georgia, patented a roller gin that fed itself and could be driven by water, wind or animals.

![An open wooden saw gin on a legged frame: seed cotton in a hopper over curved iron ribs, a row of circular saws below them, a bristle brush cylinder behind, a lint box at the back right and bare seeds on a sloping board in front, a few falling off its end](https://lastcodex.org/_astro/v2.CGYjNrt__cUv11.webp)
_In the saw gin, the teeth drag the fibre between the ribs and a brush strips it off; the seed cannot pass._

In 1793 Eli Whitney, a New Englander staying at Mulberry Grove, the Georgia plantation of Catharine Greene, built a gin of a different kind. Rows of iron wire teeth set in a wooden cylinder pulled the fibre through narrow slots in a bar, and a brush cleared the teeth. Whitney wrote that one worker cleaned fifty pounds of lint a day with it. He received his patent on 14 March 1794. His gin worked in batches, as the box had to be emptied of bare seed before it was filled again, and the wire teeth worked loose. Within a few years circular saws replaced them, and an open bottom let the seed fall out continuously. Who first used saws is disputed. John Barcley showed a model with saws at Natchez in 1795, and Hodgen Holmes of Augusta received a patent for a saw gin in 1796, which the courts voided in 1802. Whitney and his partner Phineas Miller spent years suing makers who copied his gin, and Whitney earned little from it.

The saw gin made Upland cotton, which grows well inland, profitable to clean in bulk. Planters grew more cotton on more land across the interior of the South. The gin saved labour at one step only, since the crop still had to be grown and picked by hand, and the demand for enslaved workers rose. The National Archives counts about 700,000 enslaved people in the United States in 1790 and nearly four million in 1860. By the middle of the century the country grew about three quarters of the world's cotton. Long-staple Sea Island cotton, grown on the coast, stayed on roller gins, which spare the fibre.

Fones McCarthy of Demopolis, Alabama, patented a new roller gin in 1840. A single large roller covered with leather draws the fibre under a fixed knife that the seed cannot pass, and a second knife, moving up and down, knocks the seed away. Planters of Sea Island cotton adopted it because one machine and one operator could replace several two-roller gins. Ginning itself left the plantation during the nineteenth century, as gin houses worked by animals or water gave way to ginneries that served many growers. By the 1920s a ginnery drove several gin stands from one engine through a [line shaft](/en/inventions/line-shaft/). Saw gins still clean most Upland cotton, and roller gins descended from McCarthy's clean long-staple cotton.

## Key facts

- Oldest known gins: India, 5th–6th century CE
- Whitney's patent: 14 March 1794
- Saw gin patented by Hodgen Holmes: 1796
- Whitney's hand gin: About 50 lb (23 kg) of fibre a day, by his own account (1793)
- Enslaved people in the United States: About 700,000 in 1790, nearly 4 million in 1860

## Requires

- [Gears](https://lastcodex.org/en/inventions/gear/): Teeth that trade speed for force (c. 350 BCE)

## Leads to

- [Jeans](https://lastcodex.org/en/inventions/jeans/): Riveted work trousers of indigo twill (c. 1870)

## Sources

- [Development of the Cotton Gin (Journal of Cotton Science 24, 2020, pp. 34–43)](https://www.cotton.org/journal/2020-24/1/upload/JCS24-034.pdf), S. E. Hughs, G. A. Holt, C. B. Armijo, D. P. Whitelock, T. D. Valco, USDA-ARS / The Cotton Foundation
- [Joseph Needham and the History of Indian Technology (Indian Journal of History of Science 35.3, 2000, pp. 245–274)](https://insa.nic.in/writereaddata/UpLoadedFiles/IJHS/Vol35_3_5_IHabib.pdf), Irfan Habib, Indian National Science Academy
- [Review of Angela Lakwete, Inventing the Cotton Gin: Machine and Myth in Antebellum America (2003)](https://eh.net/book_reviews/inventing-the-cotton-gin-machine-and-myth-in-antebellum-america/), William H. Phillips, EH.Net (Economic History Association), 2004
- [Cotton Gins](https://www.georgiaencyclopedia.org/articles/history-archaeology/cotton-gins/), Elizabeth Hargrett, New Georgia Encyclopedia
- [Eli Whitney's Patent for the Cotton Gin (Prologue 36.3, 2004)](https://www.archives.gov/publications/prologue/2004/fall/cotton-gin-patent), U.S. National Archives and Records Administration
- [The Cotton Gin and Slavery](https://civilwar.si.edu/slavery_cottongin.html), National Museum of American History, Smithsonian Institution
- [Hand Churka or Roller Cotton Gin, by John M. Dunlop, 1859 (object 1880-98)](https://collection.sciencemuseumgroup.org.uk/objects/co44607), Science Museum Group
- [Fones McCarthy](https://encyclopediaofalabama.org/article/fones-mccarthy/), Encyclopedia of Alabama
- [Viral post gets it wrong on extent of slavery in 1860 (1860 census totals, from Historical Statistics of the United States)](https://www.politifact.com/factchecks/2017/aug/24/viral-image/viral-post-gets-it-wrong-extent-slavery-1860/), PolitiFact, Poynter Institute (2017)
- [Eli Whitney](https://www.asme.org/topics-resources/content/eli-whitney), American Society of Mechanical Engineers (ASME)

Fact-checked on 2026-10-18.

---

The Last Codex · https://lastcodex.org/en/inventions/cotton-gin/ · © The Last Codex. Texts, plates and figures: CC BY-NC-ND 4.0.