View Full Version : chasing .003 backlash on x&y

05-09-2007, 09:18 PM
I'm new to cnc and have put together an IH mill and CNC kit. Everything is together and working but I have approximately .003 backlash in my x and y axis. I followed the directions as far as I know, including the 1/4 turn on the ballnut and just flattening out the bearing retainer washers during setup. The gibs are in and I've tried light and heavy adjustment on them. Anyone out there with similar experiences that got it worked out?
Thanks, Shepard

05-09-2007, 10:16 PM
Hi, What style ballnuts are they? Are each each axis one 2 pass nut or 2 single nuts together on an adjustable mount? Have any pictures of them? Dave

05-10-2007, 07:49 AM
For backlash, you need to check both the ballnuts AND the thrust bearings.

I suspect the latter is your problem.


05-10-2007, 09:38 AM
I spoke with Gene, who is always very helpful, and it is likely I didn't get the ballnuts set up properly. With any luck I'll be up and running within the week.
davo727 if I've used the attatchment feature correctly the picture is from IH's website and is the ballnut used.

05-10-2007, 06:58 PM
after fiddling with the ballnut and bearings I have it at .00025. But the motor is warm so I think the bearing are a little tight.

05-10-2007, 08:00 PM
I know that stepper motors can run a little warm. I have not worked with servo's so don't know about them.


05-16-2007, 09:44 AM
what did you end up doing to the ballnuts to get the backlash sorted?

05-16-2007, 09:54 AM
HAving never even been in the same room as a mill much less adjusted a ballnut I had put NO tension on the nut. Gene suggested I loosen the axis up, then use a small allen wrench and pull till the allen wrench slips out of the collar and then tighten maybe a tad more. That worked for me. As a novice I misunderstood the website instructions but this worked and now backlash is virtually gone.