I AM a spinner so I will tell you a few basic things- When someone starts spinning yarn, it is called a singles-never a 1-ply yarn! If the spinner decides to ply it, it needs to be spun in the opposite direction of the singles that make it up. One big problem is that a derailleur will only turn the wheel in one direction. Now it IS possible to have a wheel simply for spinning singles or plying, it’s just slightly less economical. My boyfriend has a Trek mountain bike fitted with a gear shifting system that is just a lever, and tht is what gave me the idea, being able to “increase the throttle” with just a lever. If I ever come across the parts for cheap, I certainly would build it!!

great idea!

i’m not a spinner but i believe it requires at least one hand free to moderate the flow of fiber. so, i would take this design in two directions.

1. chances are in the third world a stationary bicycle is already used extensively to power micro-businesses that spin fiber into thread or yarn. try googling for images (lacking broadband, i suggest someone else search the net). this covers the small scale semi-automated production pattern.

2. for the solo spinner, a foot treadle leaving both hands free to moderate the flow of fiber is probably optimal for a human powered spinning operation.

see also

http://en.wikipedia.org/wiki/Spinning_(textiles)#Contemporary_hand_spinning

love, dad