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« on: March 20, 2011, 05:21:45 AM »
The way I worked out what the min torque I would need for my lathe was to mount a bar 2m long to the end of the ball screw by the middle of the bar. I then used a load of weights and added them to one end of the bar until I got movement then weighed the weights. That way I was able to work out what Nm I needed.
Reason I used a 2m bar was so that the bar fixed by the centre would balance itself and thus only the weights would have any influence. You could use a shorter bar and just calculate on the length. Likewise if you wanted to use Ft pounds it would be a similar process. Instead of weights you could use a spring balance scale to pull the end of the bar, I used weights as I needed a big torque and didnt have a balance big enough but with your gearing I would imagine the torque required will be quite small.
Speed is easy enought to work out as any motor you purchase should have a V/1000rpm constant so with your 117v supply you will be able to work out what speed you will get when you take into account the reductions.
Oh and one last thing, when you are looking for a motor be carefull as often the hobby oriented venders give you a peak torque rating, you really want to use the constant rating.
Hood