Z hight setting off using bitzero

I just up graded to the z-plus and have noticed that when I set the z hight with the bitzero it is off. It sets it about 1.127 deeper. X and Y seem fine. I don’t remember have this with the belt drive Z. Only thing I noticed it seems to push down really hard when setting the hight. Hard enough to push the bitzero corner down. If I don’t hold it down it sets the depth really deep. Not a big deal because most of the time I set it with a sheet of paper. Just wondering if anyone else has had this problem.

It should be spot on — just make sure you have:

  • set the machine for a Z-Plus, not HDZ Z-axis
  • are positioning the BitZero to match how you are probing per:

Human error was my fist thought but feel confident that it is not the issue. I’m not fully convinced it’s a bitzero issue either. So it worked perfectly before I upgraded to the z plus and spindle. My thought is the issue is being caused by grounding on the bit in the spindle and getting a weak connection with the bit setter. If I hold down the corner and try and set the Z height it pushes down with a decent amount of pressure. My plan tomorrow is to pull the spindle and try setting the height with the router.

It seems to me the electrical connection upon contact is not happening at all, since it really shouldn’t push at all on the BitZero, the normal behavior is that as soon as it detects electrical contact, the bit backs off. Probably, the probing movement finally stops because CM reached the max probing distance, regardless of what your stock is.

What does the LED look like before/during probing? Does it properly go from green to red when testing it manually ?

My guess would be that while upgrading the machine, you may have moved something and the probe connection is now loose? The manual/LED test should tell you whether electrical contact is detected or not

1 Like

@Julien. From what I can tell the probe is working properly. Light is green until I touch it with the clip then it turns red.

I feel fairly confident that human error was cause the excessive down force. I changed to a brand new bit and that fixed that problem. Old bit had a lot of buildup on the bottom.

Now it is setting the zero 3mm below the work surface. Very consistent across the spindle and router.

From what I can tell when I set it with the paper it seems to cut the right depth. I have not confirmed it but when I set it to cut just slightly thicker than 3/4 it just cuts the tape below. With the touch probe it’s cutting well into the waste board.

Would this be a connection issue? If so how? Thanks for your help.

Ah, right, the buildup was probably electrically isolating the endmill, until after pushing hard enough the endmill ended up contacting the probe “through the buildup”, that would explain what you were seeing, and then there is nothing wrong with the electrical connection.

The 3mm offset is something else. First question, do you probe for X,Y separately then Z, or probe for XYZ ? And how exactly do you place the probe on the stock when doing so ? A common pitfall is probing for Z only while overhanging the probe lip (which should only be done when probing XYZ)

The lip is about 2mm high, so if you place the probe on the corner (overhanging) and then probe Z only, your Z zero will be set 2mm deeper than it should.

2 Likes

@Julien interestingly it’s is off by 3mm when setting z the wrong way. Probe set in the corner all they way down. When set the right way it is off by 1.127.

How would I check to see if X and Y are off. I’m curious if X and Y are off the same amount.

If I set X and Y should the bit just touch on the corresponding side?

If it’s off thus, please check that your steps / mm for the Z-axis are correct — do you have a Z-Plus (leadscrew), but are setting for an HDZ (ballscrew) or vice versa?

After probing XYZ (with the probe overhanging the stock corner), you can remove the probe and manually jog until the center of the endmill is right over the corner of the stock, and check with X and Y coordinates are close to zero.

It depends on whether you select Probe XYZ, Probe X, Probe Y, or Probe Z: you can check the videos in the user guide Will linked for illustration

But first check the nb of steps per mm as Will said. Either go in the Settings menu and double-check that you have “Z-plus” for Z axis type, not HDZ. Or open the log window, go to the MDI tab, send $$, and check the value of parameter $102

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.