X2 CNC Conversion

[Hawkeye]

I'd naturally like to have more resolution, but there were problems with movement and accuracy. The lower resolution makes it run properly. It's n ot for production, so that will be fine.

[dallen]

how big are your motors, I have one I been working on for a while now still a ways away for getting it to cut anything but getting there.

[Hawkeye]

The motors are NEMA 34 with 878 oz/in. of torque. They are WAY stronger than needed for an X2. I think most use NEMA 23 motors for this size.

Last night, I wondered why the Z-axis seemed to be a bit twitchy. Turned out I had tightened the gib lock. The motor still moved it, but the ballnut bracket was flexing a bit. Like I say, very powerful.

[Hawkeye]

After my house fire a couple of years ago, I thought I had the little CNC running again, with a treadmill motor as a replacement for the seized motor and dead controller. Then it started getting really inaccurate and unreliable. I tried all sorts of things to no avail, then finally gave up.

More recently, I built a 3D printer, which has yet to become useful. In the early going, the Y-axis stepper was really jerky and useless. That turned out to be a loose connection on the stepper cable.

Today, I finally got around to applying that info to the CNC mill. I found a loose wire on the X-axis cable. My mill is back! Right now, I'm setting it up to cut a foam plug for a cast aluminum cover for the oil filter on my Aspencade. After the fire they threw away the hot-wire attachment I had made before, so I had made another one.

So, if you've got jittery steppers, it could be settings, but it might be as simple as a bad connection. Go over them like you expect to find one.

[rleete]

I know this is an old thread, but I have a couple of questions on the conversion, as I am considering it for my mill.

First off, is it possible to still use the machine as a manual mill? Will doing so damage the motors in any way, assuming power is not applied when cranking handles?

Is there a major advantage to converting a mill (in my case a Grizzly 8689) over buying a separate cnc router? I know the router isn't as powerful, but then again the Grizzly isn't exactly a Bridgeport, either. I'm looking to cut brass, aluminum and mild steel, up to about 1/2" thick. Multiple passes are required with my current setup anyway.

[Hawkeye]

I've often thought that I should have bought steppers with double-ended shafts, so I could crank the table by hand.

As to whether it would harm the steppers, I recently built a stepper drive for a telescope equatorial drive. Since it is connected to the worm by a 1:1 belt system, it was easy to add a small crank. When I disable the motor, it is easy to crank the RA quickly to wherever I need it.

The interesting thing is that, when the power to the control system is off and I crank the RA, the LED on the control unit lights up. The stepper makes a good generator.