[Coco] leading to that CNC Coco machine (George Ramsower)
gene.heskett at verizon.net
Thu Feb 7 13:22:10 EST 2008
On Thursday 07 February 2008, Andrew wrote:
>All I can say so far is "wow!" - I can't wait to see it finished.
>What are you using for steppers (maybe you have already noted this
>before?), and what are you using for coupling (between the stepper and
>the threaded rod), and what are you using for anti-backlash (or are you
>using any anti-backlash system)?
>I have a Harbor Freight Micro Mill that someday I plan on making CNC as
>well. My biggest problem is getting the parts to turn it into such a
>mill (it seems like littlemachineshop is always out of the size of
>end-mill holder I need - 2MT 3/8" - unfortunately, it came with a
>regular drill chuck - I don't understand why HF/Sieg does this, then
>doesn't stock collets or anything else for mills), plus attendant costs,
>etc. But one day I will get there.
I found it too small and poorly made designwise, but rather than toss my
investment, I threw even more money at it. And I'm still working on it.
I have a motor mount about half done for a 4" rotary table to go with it as a
4th axis in the control program, emc.
In addition to a xylotext 262 oz motor kit, I've put the bigger table stuff on
it that Little Machine Shop sells, and the z axis you see is the second
redesign, the first one just replaced that flimsy drive screw up the back of
the post with some 10 tpi acme, which was adequate but the short gibs of the
head slider just bound up when I tried to drill a hole under cnc control, so
the current z axis setup is as shown here:
<http://gene.homelinux.net:85/gene/emc> in some of the pix. By putting the
screw in front of the post, I can now drill holes of 3/16" or so under
control from emc. I have even stronger, but of course slower motors already
on site, so the motor driving the z axis will be replaced with one of the 430
oz/in versions, and that 262 oz/in in the pictures will go on the rotary
table. Rapid moves are held to about 17 ipm with this setup as the xy screws
are still the 20 tpi original but longer, needs more motor voltage than the
driver can handle to go any faster, currently 28 volts. And it moves just as
easily at .0001" a minute for polishing operations under emc's able control.
emc is of course a linux program, very capable and just as free.
For the person who mentioned Mazak, emc has replaced the Mazak controller in
several shops now, with a far more capable bit of software. Its also running
a nearly 200 ton machine at one of the auto makers. In other words, this
ain't toy software just because its free. The latest version can handle 9
axis's of motion simultainiously.
I'm not saying this is the only way to do it. If I was schmardt, I would have
bought an X3 in the first place, and may yet if my sugar doesn't finish me
first, but hindsight is as always, 20-10.
This motor mount is teaching me something else too, that 7x12 lathe is about
1/4 the size of machine I need, you wouldn't believe some of the contortions
I've put it through to find half that motor mount I just knew was hiding in a
3.2" x 3.2" x 4" block of alu. Right now I'm in the middle of making a
boring bar about 10x the size of what I have in order to finish boring it
out. Fun its not as I don't have a powered hacksaw.
I think George is doing some pretty amazing things too. And his shop is
probably 20F warmer about now. :)
>I am glad to see the progress you are making - and I love the CoCo 3
>re-pack! I am not sure how you got everything in there (that would be a
>great thing to see in itself), but it is amazing you did!
yeah, we need some pix of that repack, with the covers off. :)
>-- Andrew L. Ayers
>Coco mailing list
>Coco at maltedmedia.com
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