On Jan 22, 2014, at 10:25 AM, Jon Elson <[email protected]> wrote:
> On 01/21/2014 11:10 PM, Jeshua Lacock wrote: >> Greetings, >> >> I am the proud new owner of an Bolton Tools AT750 combination lathe and mill >> see here: >> >> <http://3DTOPO.com/Bolton-AT750.jpg> >> >> I am super impressed with the machine so far. >> >> > Ugh, we have a somewhat similar machine at work, it is > pretty awful. > I wish you'd asked here before buying it. there are so many > limitations in workspace, etc. it is a real pain to do > anything bigger than > a thimble in size. Hi Jon, Hmmm, what machine are you referring to? I just checked and I have full 8x12x3 inches of travel for the mill. I have been using it to lathe hardened steel shafts and has been turning like a dream so far. Haven't yet milled anything though. > Will you be using the original leadscrews? They have a lot of > backlash. If you tighten a vise on the "table" it binds the > Y travel. The Z mechanism is really laughable, backlash between > the quill and pinion is probably several mm. I did a > square-column > mill some time ago and replaced the Z rack and pinion with an > eBay ballscrew. The X and Y screws on that machine were quite > tolerable. I figured backlash was common to just about all reasonably priced mills, and I was wondering what folks did with them to compensate with CNC. I just checked the backlash on my Z and with the micro-adjust knob I can not feel any discernible backlash. I certainly can feel backlash on the Z quick feed and on the X and Y leadscrews. Eventually I would like to replace them with anti-backlash ballscrews. I would like to get the machine up and running first if I can expect reasonable results from it. I think I read somewhere a while back someone compensated for the backlash in software and virtually eliminated the problem without having to replace the leadscrews. Speaking of anti-backlash ballscrews, have you guys seen this printable: http://www.thingiverse.com/thing:125529 I have printed them out - and they work amazing! On a 3/4" shaft it takes over 100 pounds of force before it slips - and you can pretty much make it tight as you like within reason. NIce thing is it just slips too - no damage when overloaded. It is also configureable for travel per revolution. > The Pico USC will be fine, but depending on the drivers used, > may not be necessary. If you use Gecko drives with the 10 X > microstepping, the USC starts to look good due to the required > step rate. The Gecko drivers are VERY good. Yeah I was planning on going with Gecko. Good to know, thanks Jon! I guess the biggest uncertainty right now is how much torque I might need on a machine like this. I was guessing something like the first stepper listed here: http://www.kelinginc.net/NEMA23Motor.html Cheers, Jeshua Lacock Founder/Engineer 3DTOPO Incorporated <http://3DTOPO.com> Phone: 208.462.4171 ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
