Newbie- X1 X-axis sticking

[rincewind23]

Hi all,

Before I start, this may all sound like a pretty vague question - but hopefully someone's seen this before....

I'm converting my Sieg X1 (well, actually I got it from Axminster in the UK and I've been told it's the same as the Sieg, just badged and painted differently) for CNC. I have made some mounts for the stepper motors, and hooked them up with EMC2 software via some stepper drivers.

The Y-axis is fine - the test utility with EMC2 allows me to manually run the steppers backwards and forwards, and the Y-Axis travels fine. The X-axis is another matter, though. Without the brackets on, the leadscrew moves fine. As soon as I tighten the bracket up, the leadscrew is unable to turn. I've checked the bracket, and there's nowhere it directly touches the screw - all it does is tighten the bearing block against the table (just like it was when it was manual with just the hand crank on the end). I'm pretty sure the tightening doesn't shift the bearing block at all to bind on the leadscrew shaft.

Has anyone seen this before? Without the table on, the lead screw has a lot of lateral movement in the nut block, I don't know if this has anything to do with it.

Like others on here, this is my first foray into milling/CNC so any (even basic) suggestions gratefully welcomed.

Cheers,
KEv.

[darkith]

What do you mean by "bracket"? Is this the stepper mount?

D.

[rincewind23]

Yes - It's what I built to hold the bearing block tight to the table, house the lovejoy coupling between the leadscrew and the stepper, and mount the stepper. It's not perfect, but it's the same as the one on the y-axis which is working fine. I was planning to use these rough parts to machine better ones through CNC

[darkith]

Hrm. Hard to say without seeing the setup. I'm assuming you're using the bearing block screws to hold both the bracket and bearing block onto the table, and that the bracket is on the outside of the bearing block? (you'd be asking for trouble if you tried to clamp it between the table and bearing block).
I'm also assuming that you haven't connected the stepper and lovejoy coupler yet, as any misalignment there would be the obvious answer.

I'd watch for these possible problems:
-bracket has non-parallel faces, so bearing block cants when bracket tightened, tilts leadscrew
-bearing block has non-parallel faces, so bearing block cants when larger face of bracket is tightened against it, tilts leadscrew
-bearing block shifts up or down when bracket tightened, binds on screw. (maybe caused by flash around bracket drill hole "centering" in screwhole)

D.

[rincewind23]

Thanks! I'll check all these and report back. I might even include pictures

Cheers,
KEv.

[FlyingElectron]

Sounds like you may have some misalignment on the X axis mount. Loosen everything up, try moving the table so the distance between the X axis mount and the X axis nut is as short as possible (move the table all the way to the left if you motor is on the right side of the table), then retighten the x axis mount. This should cut down on the misalignment.

I've also got a CNCed X1. Have you installed bearings on the X and Y axis? The stock setup without bearings is ok when used with the handwheels but is likely to bind and cause you to lose steps with stepper motors.

[rincewind23]

Yup - looks like there's some play in the bearing block when tightening it up - this time I checked that the lead screw was still free every half a turn until the block was tight on, nudging the block if the screw was tightening.

All I need to do now is "debug" my stepper controllers - one's working fine but I have two non-working ones (that did work to start with..)

Thanks to all for the help!

[darkith]

You didn't unplug the stepper motors while the boards were on, did you? That lets the magic smoke out on most boards.

D.

PS. You don't wear a hat saying "WIZZARD" do you?

[rincewind23]

No, and no