You may remember from a few months ago, I was planning on building a big router. Well, time to ice down the ol' credit cards, parts are coming in next week!
Details are this:
2 x 3 x 1 meter work envelope
THK 30mm SHS rails all around
THK 50mm Diameter ball screws on all three axes, all with rotating ball nuts.
2 sealed, caged ball bearing blocks on each rail
Steel frame, bolted, not welded
4x6" rectangle tube, quarter inch wall
3x4" rectangle wall, 5/16 inch wall
Total mass looks to be in the 3000 lb range, minus servos and table top. Thanks to the people who gave me the advice of "Figure out the weight before you size your servos! They're heavier than you think!" I'm always building stuff, but this one really shocked me - almost 500 lbs for the gantry!
Here's MY big piece of advice to all of you who have a big, expensive project in mind..
CHECK DIFFERENT DISTRIBUTORS FOR YOUR LINEAR COMPONENTS!!!
Even if they all come from the same manufacturer, the cost differences can be HUGE!
Example, one place quoted me $1920 for a SINGLE 3 meter long, 30mm rail with one block, with 10 weeks shipped from Japan.
The next place quoted me $570 for the exact same rail, and $240 for TWO blocks.... ships from Ohio, IN A WEEK.
All told, going to a different distributor saved me over $4000 and NINE WEEKS. Thank you Kaman! (serving New York City)
Also, for anybody wanting to build a good, small machine, the http://www.tos-world.com/ website is pretty good, plus it illustrates a pretty good point... which surprised the hell out of me...Using a rotating ball nut is CHEAPER than using a fixed nut and rotating screw when you factor in the expense of using two proper bearing blocks at each end of the rotating screw PLUS your regular ball nut.