Originally Posted by
Gads
hi all I could use some input on a new machine build i'm trying to work out.
my plan is a 55x70 or 60x60 moving gantry router machine. all riding on roller bearings. my gantry is 8020 (3060) with porter cable variable speed router, weight without my slide stuff at this point is about 50lbs and estimate total finished weight between 50-100lbs. my steppers are 640oz 4 wire motors and gecko's i have running my mill right now. my thought is to use hi-lead 3/4-.500 multistart acme with plastic nuts on x and y. the x i plan on using 2 screws coupled with belt/pulley and no gear reduction on any axis. I have tried to calculate screw torque requirements, critical speed and desired ipm etc.. but am no engineer. my thoughts are based on 20-150ipm feed and 200+ rapids keeping my motor rpms below maybe 700rpm. any experience or advise would be welcomed as i need to make a decision before my toy goes any further.
Thanks all
For considerably less than the amount of expense that you will incur by using 3/4" multi-start lead screws, bearings, end supports, anti-backlash nuts, rails, and other parts, you could use cncrouterparts.com rack and pinion drive assemblies and carriages. You will then have none of the whipping issues and easily get 1400+ ipm jog speeds. Everything about them is easier to figure out and to install. Anyone designing a machine with over 3-1/2 feet of travel should seriously consider using them.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com