Carl, thanks but those generics aren't helping me. I know any CAD can draw a circle. I also know what CAM does. And while there might not be "lathe CAD" there are big differences between 2D and 3D and full view and half profile. I did quite a bit of reading/viewing and hands-on research before here. Have you ever drawn a circle in CAD and converted it to g-code for a lathe? (I guess that could be used to turn a fat rod into a skinny rod). I've tried, couldn't get it to work consistently. It turns out that mach3 doesn't want to be fed a circle, it wants to be fed a half-profile 2D view, and a half-profile 2D view of a circle is a line. If you have a specific CAD that you have used to draw for a lathe then please let me know, and let me know if you've drawn it in 3D/2D, full or half profile, and had it work on a lathe, please let me know what 2 programs you used that worked. Those are the specifics that I'm looking for and I appreciate any specific information that you or anybody who has done it can give me.

Lee - thanks! That is the sort of information I was looking for. I had almost figured out the partial profile part the hard way - I tried drawing in 3D and then exporting, but mach3 consistently said it wasn't a valid lathe file. Then I tried a full 2D shot, and had the same problem. When I would slice the full 2D profile into half I'd get a few of them to work. But a lot of them would have errors because the axis weren't aligned correctly or I had some line extending too far into the negative. That told me half 2D profile might be the way to go, but that positioning properly on the axis when drawing seems to have something to do with it too.

I can get turbocad 18 fairly cheaply. If 2D is fairly easy to learn then I could give it a try. When you have drawn in turbocad for your lathe, do you do full 2D and slice in half, or just the half profile? And do you have to do anything special with the alignment/axis before exporting?

thank again
Joe-at-CNC.


For anybody else out there who has done it - what CAD did you use, did you start in 3D or 2D and compress/slice it first, or 2D full profile and then slice, or just 2D half profile? Did you find it easy enough with your program that you'd recommend it?

And a follow-up on openSCAD - I found that easy to learn. But because of the way it does curves (It doesn't really do arcs) there is no easy way to do a 2D half-profile, and all my attempts at converting/slicing a 3D view have failed, so it looks like that one's off my list for now.