Ball Screws & Nut Advice

[coolman]

Hello,

I am building a metal mill using 3" x 3" x 0.25" mild steel square tubing. The x-axis (gantry) measures 62" across. I need to buy some Ball Screws & Nuts. This means I need to buy a 62" Ball Screw. My question is what diameter size Ball Screws should I get such that the 62" ball screw does not bend? The diameter choices are 5/8", 3/4", or 1". Of course the bigger the diameter the more expensive. Backlash and or bad stuff happens when the screw bends or whips. Is there any other advice that I need to determine the size of the ball screws I need? Also, what is the difference between a round or square ball nut? The square one is cheaper.

I tried uploading a picture but the file is too big. Does anyone know of a program to resize a jpeg file?

Thanks,

[ger21]

http://www.nookind.com/ball/BallCalculators.cfm