New Problem for me

[OldDog (Kent Bunch)]

Can anyone tell me what causes this I am guessing something has come loose or slipped. It started out very slight and has gotten very bad . any help on what might be the problem would be Great… Thanks Kent…

[mhotchin (Michael Hotchin)]

What kind of Z do you have?

With the power on (so everything is locked), if you try to move the spindle up-and-down, is there any movement?

Could be

• bit slipping in the collet. Clean oil off everything, look for debris in the collet or receiver
• (for Z plus) backlash on the nut

[WillAdams (William Adams (Carbide 3D))]

If everything is mechanically sound, one way to address this is by adjusting the depth per pass so that the final pass removes a very thin thickness of material. e.g., if cutting an 0.5" pocket and depth per pass is 0.125", reduce it to 0.124, so instead of 5 full depth passes, one gets 4 passes as 0.124", then a final pass which only removes 0.004" of material.

[OldDog (Kent Bunch)]

No movement I have Z plus Z I will clean collet and receiver. But what do you mean by backlash on nut. Please… and thank you!!

[OldDog (Kent Bunch)]

Thanks Will I was only cutting. A.0625 depth using a .0625 bit. and it was my thought to re carve again and running at a slightly deeper depth. to try and recover this sign. I had a couple of great ideas from Michael H. I will try also Thank again I will keep you posted

[mhotchin (Michael Hotchin)]

The ZPlus uses a leadscrew (not a ball screw), with a nut. If the nut is loose on the threads, then the Z axis can move up-and-down by whatever amount the nut is loose.

There are ways to minimize the problem - using an anti-backlash nut (which the Z plus uses), or switching to the more expensive ballscrew (as used by the HDZ). The anti-backlash nuts can wear out over time.

Z-Plus Leadscrew Nut Replacement - How To Guide

I was having issues with excessive depth of cut that I finally tracked down to a worn leadscrew main nut/anti-backlash nut assembly, documented here: Z-Plus play/backlash question Support was kind enough to expedite repair parts, it took about 20 mins to replace and was easy enough to do. Here are the steps for anyone else with the same problem. This is the assembly that needs replacement. Note that the nuts are plastic (feels like nylon or similar). The main nut is held on with the 2 screws a…

[dandangerous (Dan Dornback)]

I would also suggest checking the v-wheels on all axes, make sure they are snug. Rotating a wheel should move the assembly (snug but not too tight…). If you can spin a wheel it is too loose. That leads to the axis rocking/lifting/moving when it should be firm.

Router bearings are another one - when I fixed the Z-plus in the post @mhotchin referenced, also discovered my router bearings were toast. This is the rebuild on the Dewalt 611:

Dewalt 611 Bearing Rebuild

Been troubleshooting some cut issues for a while, after fixing and eliminating a lot of other problems (loose v-wheels, stretched belts) finally got down to bearing play on the router. I didn’t measure it, but could grab the collet and feel the physical movement up and down. I’d guess at around 0.005 - 0.008" range based on the cuts I was was seeing, which really showed up in aluminum. So, time for a rebuild! I looked around and could not find comprehensive instructions on what’s needed and how…

Also - depending on your machine (I have the SO3 XXL) - bed deflection. Mine was getting about 1.5 mm of downward deflection in the middle with light pressure. Fixed that here:

SO3 XXL Bed Deflection - Center Support Solution

A while back I noticed considerable deflection in my SO3 XXL bed while cutting aluminum. During the plunge the bed would push down and then slowly raise back as the cut progressed. Did some measurement with my dial gauge and it was about 1.5mm of downward deflection with light pressure. The rails on the SO3 XXL are actually convex, mine had a ~6mm rise at the center. Hard to capture in a pic: [image] Under load, when fully assembled with the weight of the bed, etc., this rise levels out and …

I was seeing a similar thing to you, turned out it wasn’t one thing, rather a combination of multiple small problems amplifying together and translating to bad cuts.