W. Jacobs wrote: > Hello All, > I am new, real new to the cnc world. I want to convert a small bench > top mill into a cnc machine. I have wanted to do this for a long time > and about a week or two ago, I found the linuxCNC.org web site. I have > not at this time found a computer I want to use and am looking for one. > > I have wanted to do this project for a long time. Because of that, > Years ago, I found 3 rather husky stepper motors that I thought would be > usable and bought them. They have been sitting on a shelf for a long > time. > > I looked at stepper drivers the other day and thought they were rather > expensive. A 3 axis unit was just over $300. That seems like a lot of > money to me. It is my understanding that the printer port of the > computer has 2 lines per axis. One line tells direction and the other > says to take a step now. That seems pretty elementary to me. It should > use a small micro controller, and 4 transistors for each axis. > > I had planed to belt drive the lead screws with a timing belt and use a > stepper motor that has 200 steps per revolution. This will give > resolution of about .0005 inch per step. I may half step, but I see no > reason to micro step. > > Am I missing something? Is there more here than I think? Is my concept > of the data on the printer port wrong? Any light on the situation would > be helpful > > Thanks > bill
You don't actually say how big your steppers are. "Husky" is not a number... The relevant specs are current, voltage, and frame size, roughly in that order. There tend to be two classes of motors (and drives) in the hobby CNC world. Motors under 2 or 2.5 amps are usually NEMA 23 frames, and are suitable for micro-mills and mini-mills. Micromills are the ones that you can pick up without straining - Sherline, MaxNC, etc. Minimills are a bit bigger, maybe 150 lbs or so. Motors from 3 to 7 amps are usually NEMA 34 frames, and are sized for larger machines, like mill-drills (400-700 lb machines). Bridgeport class machines usually use something bigger yet. In the "under 2.5 amp" catagory you have drives like Xylotex and others, which normally run in the neighborhood of $30-70 per channel. When you get up to 3-7A motors, that is Gecko or similar, at $100-200 per channel. Tell us what class of machine and motors you have, and I'm sure more suggestions will be forthcoming. Regards, John Kasunich ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
