I would like to make an electric motor powered soil sifter for sifting soil/compost, but I'm a bit stumped at the moment. I'd like to use an inexpensive single phase AC motor from a an old vacuum cleaner or a clothes dryer, but I don't know how to determine what size electric motor I would need for my application. Basically, the motor has to have enough torque to move a wire cloth screen fast enough below a maximum 20 lb load of soil to shake/scrape the soil into bits so it will easily fall through the screen. I've included a few details below to hopefully help whoever can help me to determine what size motor would be right for my application: Motor: Motor HP: ? Motor torque: ? (is full-load torque what I should be calulating? How to compute how much is required?) Drive: motor (drive) pulley ": 1 driven pulley ": 8 (a plate & drive pin/rod will be attached to this pulley) belt: A style belt Sifter: inside frame dims: (1.5"H x 24"L x 18"W) wire cloth: 1/4" square openings Wt: 2 lbs Load: wt: 20 lbs material: soil/compost sift rate/second: 2.2 (driven pulley rpm=132) I did some HP & torque formula calculations to determine what size motor I thought I might need for my application, but I am not really confident about my numbers. I don't want to use too small of a motor and discover it doesn't work properly or too large of a motor and waste electricity unnecessarily. Can anyone let me know how to solve these questions? Thanks in advance for any help you are willing to provide.