On 4/21/2015 6:15 AM, Erik Friesen wrote: > Perhaps my sights are set too high here, but I have looked at this - > http://www.ebay.com/itm/261855407885 - as well, but it looks a bit flimsy > on the X axis to me. Also, how ever do you get the thing from twisting?
There are software ways to run a gantry with two motors and keep them in synch. Many 3D printers do that for the Z axis. My preference is a mechanical linkage. Torchmate runs a shaft across their gantry to a rack and pinion on both sides. If you want lengthwise screws you can connect them at both ends with chains or belts. Another method uses a cross shaft on the gantry with stationary chains or belts on the sides that loop through sprockets or cogged pulleys. I've seen that method with a belt to run the tool carriage across the gantry. YouTube videos of homebrew/DIY CNC gantry machines show many different ways to put them together. Here are just three of the large number. Chain drive https://www.youtube.com/watch?v=0MHl2N8viKc Same concept with a belt https://www.youtube.com/watch?v=OdJoVh6DRPA Chains with a cross shaft https://www.youtube.com/watch?v=vETkf1sqo3M > I find it hard to understand how you weld up your own frame and get it flat > and square, unless you have the right tools to do so. First you need a level assembly area. That can be as basic as four jack stands with flat plates on top, all carefully shimmed to the exact height/level. Weld the bases down to steel plates so weight can be piled on. Put the pieces of the frame on the stands, check for level, clamp then tack weld to each other and to the stands. Alternate welding short bits at each corner. For big frames you'll need stands in the middle of the long sections. Once you have the main frame welded together flat and true you can weld on other pieces as you build it upside down. Cut it loose from the stands, flip over, tack back down and finish the top. Or if you welded legs on while it was on the stands, move it to its final location, level it and attach it to the floor then finish welding on the top side parts. Or you could start by attaching the legs to the floor, shimming them all to be level with each other, then build the table in place. Once you get enough pieces welded together it's not going to bend or twist. --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com ------------------------------------------------------------------------------ BPM Camp - Free Virtual Workshop May 6th at 10am PDT/1PM EDT Develop your own process in accordance with the BPMN 2 standard Learn Process modeling best practices with Bonita BPM through live exercises http://www.bonitasoft.com/be-part-of-it/events/bpm-camp-virtual- event?utm_ source=Sourceforge_BPM_Camp_5_6_15&utm_medium=email&utm_campaign=VA_SF _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
