Z drops 0.010" in middle of X axis

[MikeC]

I've had my HS1 for a little over a year now. I have been having a lot of trouble getting my z depth consistent across the X axis. The problem is that the left and right side of the table are the same height but the cutter dips in the middle of the X axis travel. If I fly cut the table and then place a parallel across it there is a huge gap visible in the middle of the table.

I have taken the machine apart, cleaned all parts and reassembled. The pulleys are tightened just snug and the problem is still there.

Any suggestions on what could be causing this?

[MikeC]

I would like to clarify that the cutter is what is dropping 0.010" not the actual Z Axis.

It's as if the x bridge is twisted slightly at the middle so that the cutter is brought closer to the table.

I figured it was being caused by one of the bearing surfaces on the x travel being out of flat.

I just can't figure out an easy way to measure which bearing surface could be causing it.

[georgemyers]

Mike

Sounds like you have done some in depth troubleshooting.

The only thing I would try next since you suspect the gantry is to take it apart and start measuring to insure it or the rail is not twisted or bent and level from end to end.. I have ran my z into the table a few times hard enough where it looked like the entire gantry was tilted back a bit, so far the only thing this caused me was a v-wheel bolt working it's way loose.

From the little I know about troubleshooting going by your description it does sound like it may the gantry or gantry rail may be the source of your problem.

[romaxxcnc]

Hi Mike,

Could be a bad V-wheel or the rail is worn in the center causing what you're seeing. Then again It could be the table or the workpiece not being secured in the center, and it's actually a small bit of resonance in the table workpiece giving the effect that it's cutting deeper in the center.

Let me know, Ron

[dbstrings]

I’m having a similar issue. Drop is more than .015, I can slide a piece of wood veneer under my straightedge freely.

I have screwed a new spoil board overtop the original table on my WD-1. After facing I checked to insure it was square and it was not. I ran the spindle manually in jog afterward to see if maybe the program was bad in some way. I got the same result. I ran the spindle across the board turned off to test Ron’s frequency theory, it followed the deflection perfectly.

Any further advice on this? What was your avenue to fix this, OP?