G0704 need some tips on Z axis

[macatoms]

I need a little help on my mach3 config on my z .Iam using a kelig 8060 drive set to 1/2 step 6amps.I am running stock screws.I am not to sure on the screw pitch if its metric or standard.If some one could give me a good starting point to put into mach that would be great.Thanks

[hoss2006]

I just rewatched the video "Stock Screws Calibrating the Z Axis" on my dvdrom and if you
are running direct drive on the Z, 1/2 step mode, 2400 steps/per in motor tuning should get you really close.
I can upload it to youtube if you want, could help though.
Hoss

[macatoms]

Thanks Hoss,I am running a belt drive like the one on your video with 1to1 ratio on the pulleys.

[hoss2006]

That's the same as direct drive so 2400 should be good, I had 4802 in the video with a 2:1 belt drive after calibrating.
Hoss

[macatoms]

I have my xand y set at 4000 with 1/8 step is that ok?Do you have a better set up on xand y.I am learning this stuff as fast as I can but wow its hard there is so much info to learn.Any help is awesome.Thanks

[hoss2006]

I believe I ran 1/2 step mode on the x and y too so that would be 4000 steps/per, 1/8 mode would be 16000 steps/per.
You can see if your steps per are close by zeroing the axis, running "G0 X1.0" in the MDI input and see if the table
moved 1 inch, the scale on the front is useful for this.
Hoss

[macatoms]

Thanks for the tip I will change that over on the x&y.Also at some rapid speeds like in jog the screws make a strange noise,its almost like a resonance vibration or something?I don't know it seems to be ok on damage from it but it still makes my rear end pucker.Have you come across anything like that in your travels?

[hoss2006]

It could be vibration at the lead screw nut, have you adjusted them to remove backlash?
Sometimes the 2 screws back off, a little loctite on them when readjusted can keep them in place.
Also make sure the 2 screws locking the entire nut in the slots are tight.
Hoss

[Nater]

Also make sure the 2 screws locking the entire nut in the slots are tight.
Hoss

Yeah I was looking at that last night on mine. It sure doesn't look like they engage the nut much. Does the nut need to be level to operate correctly? I noticed mine is at a good 15 degree slant. (so maybe only one screw is engaged?)

[hoss2006]

Slanted as looking from the x axis like in the pic?
It can be off a little that way and be fine but its easy enough to loosen the 2 screws in the saddle and
rotate it with your fingers to make it more vertical and retighten.
Tilted too much and a corner could rub the underneath of the table
Hoss

[Nater]

@Hoss - I started my own thread over here if you want to take a look. Pic there in the middle somewhere showing it, but you answered my question exactly. I thought I felt a rubbing as I was removing the X-axis leadscrew, and I think it was the nut being off kilter due to loose screws. I guess I'll find out when I get everything back together after cleaning.

@macatom - how is your machine secured? Bench? Bolted to floor? Just wondering. You're not the first one I've seen with the issue you're describing.