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Unread 12-01-2013, 23:10
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Nathan Nathan is offline
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Re: VEX part strengths

Quote:
Originally Posted by efoote868 View Post
How much weight can the turntable bearing kit support,
http://www.vexrobotics.com/vex/produ.../276-1810.html

How much torque can be applied to the square bar shafts,
http://www.vexrobotics.com/vex/produ...on/shafts.html

and gears,
http://www.vexrobotics.com/276-2250.html

And lastly, is this is type of information published anywhere?
Unfortunately I don't think you're going to find that information published anywhere. I can't answer all of your questions, but you haven't gotten a reply in a few days, so I'll bite

I've never used the turntable, so I can't comment on that.

I can't give you an exact figure for how much torque the drive shafts can take, but I just tried twisting a shaft with two pairs of pliers and wasn't able to bend it permanently (it flexed a little bit, but not much at all). I think the shafts are made out of steel, so they're pretty strong (at least for a short length).

I haven't used the high strength gears, but I can tell you that the normal vex gears are pretty durable. I've really abused mine and have never had one break on me.

Quote:
Originally Posted by efoote868 View Post
There are a few design considerations. One is that we need to have slow and precise movements, probably no more than 10 degrees / second. Also we might need relatively large amounts of torque, considering the size and length of some telescopes. The motion of action on the inclination needs to be close to 90 degrees.
You might have trouble with the Vex motors for this application. For a telescope you will need torque, precision, and repeatability/accuracy, and I don't the the Vex motors will meet any of those requirements. The Vex motors don't have a lot of torque (at least not in terms of moving a heavy telescope) and without some sort of feedback (making it a closed-loop drive system) you won't have any idea how far the telescope has been panned or tilted. I would suggest looking into using stepper motors. They will have far more torque then the Vex motors, will eliminate the need for feedback, and are extremely precise.

If I were you, I would head over to cnczone.com and ask for suggestions on the mechanical side of things there. This is a very cnc-ish project.

Good luck!

Nate
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