1764 · Stanhill, near Blackburn

How the jenny worked.

One wheel, eight spindles, one spinner. Before it, a spinner made one thread at a time. Here is the machine's working cycle, slowed down.

Before: one hand, one thread.0 threads

On the old great wheel the spinner held the cotton in one hand, walked back to draw it out, and turned the wheel with the other.

The jenny: the clove is the hand, eight times over.0 threads
  1. Close the cloveA wooden clamp grips eight rovings, loose ropes of combed cotton, fed up from the bobbins below.
  2. Draw outThe spinner's left hand slides the clove along the frame. The rovings stretch thin while the right hand turns the wheel slowly.
  3. TwistThe clove stops. The wheel turns fast, the drum spins all eight spindles, and twist runs up each strand. The spindles lean, so the yarn slips off the tips as they turn.
  4. Back offA small turn backwards unwinds the coils left round the spindle tips.
  5. Faller downThe faller wire presses the eight yarns down, off the tips and onto the spindles proper.
  6. Wind onThe clove runs back in while the wheel turns, and the yarn winds onto the spindles as cops.
  7. Open and go againThe faller lifts, the clove opens, and it all starts again on the next stretch of roving.
8

spindles on the first jenny, all from one wheel. One spinner did the work of eight.

16, then 80+

sixteen spindles by the 1770 patent; later jennies ran well over eighty.

Soft yarn

jenny yarn was good for weft, too weak for warp. That took the water frame, five years later.

Small enough for a cottage, which is where most of them worked. One person, still at the wheel.

A working diagram drawn from period descriptions and museum examples: the proportions are simplified, the cycle is as the spinner ran it.