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1. ## Homemade picket twister Horse power numbers

I recently made a picket twister that has a 1/3 hp motor, 2" pulley on the motor, 8 3/4" pulley on the 50:1 worm gear.
It can twist half inch solid cold square almost enough (to the shearing point).
I didn't even try to make baskets.
So my point is that my math tells me it takes 72.83hp to get there.
When I get time I am going to try a 11 3/4" pulley on the worm gear and see what that can do.
That should give me 97.7 hp at the stock.
I'll post results.
Just wanted to put the numbers out there.
Thanks, Cargoon

2. Senior Member
Join Date
Feb 2007
Location
Near Dallas, TX
Posts
215
You can't gain horsepower by going through a gearbox (you actually loose hp). What you're gaining is torque. Actually you're trading RPMs for torque.

HP = torque * RPM / 5250

So your 1/3HP motor at 1800RPM is generating about 1 ft-lbs of torque.
When you go through the 50:1 gear reduction you'll change this to 50 ft-lbs of torque, but it'll only spin at 36 RPM.

HP = 1 * 1800 / 5250 = 0.34
HP = 50 * 36 / 5250 = 0.34

Both of these are the same horsepower. In the real world you'll lose a whatever torque it takes to spin the gearbox so the output horsepower will be a little less.

3. ## Thanks

Ok, then my motor is putting out 1ft-lb of torque.
So then it takes 218.75 ft-lb of torque, (Not counting what is lost in the worm gear).
Motor with 2" pulley, worm gear with 8.75" pulley, 50:1 worm gear.
1ft-lb(Motor) x 4.38 (pulley ratio) x 50 (Worm gear) = 219ft-lb .(Not counting loss)

So when I put on 11.75 pulley
1ft-lb x 5.88(New pulley ratio) x 50 = 293.75ft-lb (Not counting loss)

Does this sound pretty close?

I would put my torque wrench on it but I just sold my 250ft-lb. I'll see if I can borrow one from work and see how close we are.

Thanks Andy

4. I have a 979 lb in torque motor/gearbox on mine because i use that drive for 3 other machines and it works great...Bob

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