Ready to Build
Creative Commons Attribution 4.0 International License
Complete instructions for making a bicycle powered thresher. Thresher works on various crops including dry beans, wheat, rice, rye, einkorn, and lupine. Threshes about one pound per minute. This is the first of three tools for small scale grain processing designed to allow small farms to dabble in grain. The other two tools are the bicycle powered fanning mill and the bicycle powered de-huller/flour mill.
thresher
bicycle
bike powered
pedal power
seed processing
grains
SARE
I built (or modified) this tool
1 user has voted.

Comments

Tool comment

I don't suppose you have a bill of materials for this project? Maybe at least a wood list? I am planning to build from 3/4 plywood unless persuaded towards 1" planks.
Tool comment

There is no bill of materials. There are so many materials substitutions and adaptations (like plywood for 1X pine) that what i recommend is printing out the instructions (pdf link below) and then on each page of the instructions write in the materials you will use. If you plan to acquire the materials all at once you can collate the pages to make a master list. This exercise will also help you get familiar with each step in case modifications you make in your design (example: substituting 3/4" plywood for 1" pine) cause changes in dimensions and other possible changes in the instructions which will need to be penciled in to your instructions. Incidentally, i also use the instruction sheets to make other notes and to keep track of time and cost for each step.
Tool comment

The gear reduction between the exercycle and the thresher drum is not very important, and can be adjusted easily as an afterthought. Exercycles come with all sorts of gear ratios between the cranks and the flywheel. The thresher drum will work best at somewhere around 200-300 rpm. Too slow and the grain won't get threshed. Too fast and the wobble in the axis will shake the machine apart. Some wobble, remember, is good, as it shakes the seeds down. The bike chain part of the transmission will be happy with a larger ratio; the v-belt part of the transmission will be happy (there will be less friction) with a smaller ratio. In general, the flywheel stores more energy if it is turning faster (kinetic energy increases with the square of speed), so there are some reasons to have a large ratio to the flywheel (ex. 4:1 increase), and then a small ratio to the drum (ex. 1:1.2 decrease). I hope this is helpful!
Tool comment

So I just ran my first samples through this thresher today. Overall it worked pretty good. I'll see if I can post pics somehow. It threshed the hulless barley pretty well with the wood flails. The spokes did pretty good on the beans as did small chain. Now to finish the fanning mill.....
Tool comment

The rigging diminishment between the Exercycle and the thresher drum isn't essential, and can be balanced effectively as a bit of hindsight. Exercycle accompany a wide range of apparatus proportions between the wrenches and the flywheel. The thresher drum will work best at something close to 200-300 rpm. https://dissertationhelp-uk.co.uk/ Too moderate and the grain won't get sifted. Too quick and the wobble in the pivot will shake the machine separated. Some wobble, recall, is great, as it shakes the seeds down. The bicycle chain some portion of the transmission will be content with a bigger proportion; the v-belt some portion of the transmission will be upbeat (there will be less contact) with a littler proportion. When all is said in done, the flywheel stores more vitality on the off chance that it is turning quicker (motor vitality increments with the square of speed), so there are a few motivations to have an expansive proportion to the flywheel (ex. 4:1 increment), and afterward a little proportion to the drum (ex. 1:1.2 lessening). I trust this is useful!
Tool comment

I built your thresher and recently made a vid of it in action: https://youtu.be/DYG6QuU8ZCg It works pretty good. Quite good in beans but much more work to get wheat to thresh well. Cheers