Re: [CAD_CAM_EDM_DRO] CAM software

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>i'm looking for something that is free, will run under windows 98 or dos and can be downloaded from somewhere. backlash compensation would be nice too. what do you use?
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TurboCNC is a low cost program. It's downloadable from
http://www.dakeng.com (I think that's right) and is shareware. The
downloadable version is fully functional, and full registration costs
only $20. I think that's fair...free to try, and cheap to own. It
includes backlash compensation, too, but it's best to mechanically do
away with backlash, rather than compensate for it in software. BTW:
TurboCNC runs under DOS, and even runs well under FreeDOS, which
eliminates Microsoft from your machine entirely. As everyone's favorite
inside trader would say, "that's a good thing." ;-)

>ps: has anyone any experience of using cheap, ordinary studding for lead screws? i was thinking of M6 with a pitch of 1mm but i suspect it isn't amazingly accurate. the only other lead screws i can find are ludicrously priced, and the nuts are even worse! also, where might i purchase some very small milling bits suitable for PCB work?
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For a proof of concept prototype, use whatever you'd like. If you plan
even a little bit ahead, you can always upgrade the drive screws later,
to something of better quality. The theaded rod at a hardware store
should be perfectly sufficient for a learning machine.

I used 5/16"x18tpi threaded rod for my machine, and it seems to work
quite well. that diameter fits nicely inside an 8mm rollerblade
bearing, which I used to support the end. I'm not yet done with the
electronics (having some trouble with it, but Harvey is helping me
through it), but my machine moves quite smoothly under power from my
cordless drill. I made my own antibacklash nuts, for so little money
that it verges on absurd.

http://makeashorterlink.com/?C55F63745

http://www.crankorgan.com is a site that sells plans for "cheap" CNC
machines, and he uses allthread and a "floating nut" design that he
claims eliminates backlash. I didn't order his plans, but let's just
say that he inspired my machine... There's a lot to be said for
building from parts you can find locally!

The reason that the list members don't recommend allthread rod, is that
it is relatively inconsistent when used as a lead screw. The thread
form also leaves a bit to be desired. But, to just get something
moving, it works great and is available everywhere. It also has higher
friction, though my setup can be easily turned with 2 fingers -- I'm
going to use 100 oz-in steppers that I salvaged from some LASER printers.

The best advice I can give you is to just build *something*, and get it
working now. Don't try to make it utterly perfect, because no matter
how good a job you do, once you start using it you'll want to make
modifications. It's human nature. More power here, greater accuracy
there, faster motors, etc. Just plan ahead, and leave room for some of
those improvements...improvements like a better quality and possibly
larger diameter drive screw. (ACME thread is easily available in 1/2"
diameter and larger -- smaller is harder to find, especially locally)

-- Chuck Knight