Excessive play on the Z axis

While stiffening the X and Y axis on my 1000x1000 X-Carve, I have encountered a problem with excessive play where the Acme threaded rod runs through the Delrin nut. Has anyone run into this and found a way to fix it? Seems like it would need an anti backlash design of some sort.

The Delrin nut wears if the fit isn’t good between the threaded hole and your acme screw. My acme rod came in warped and, after forcing it through the nut a few times, I ended up with a small pile of black plastic shavings from the nut. I think it’s possible that excessive ware on your nut could be the result of either a Z axis assembly misalignment or even poor feedrate/spindle rpm choices. If you jog your Z up and down, can you see the threaded rod showing any signs of warping?

I tested mine last night and noticed that the acme rod looked like it was bent as the carriage moved up and down the Z axis. The rod moved side to side, not sure if it is supposed to be like that or not.

No, absolutely not.

I know what I am doing after work tonight…

Contact customer support, or whatever Inventables calls their department. If your rod is new and warped they should replace it.

Yup, thanks for your help Nathan!

This is what I’m talking about: https://youtu.be/BJKqwdgV2mw

I noticed this play in the delrin nut also. I checked my acme screw and it is straight. I guess i should order another nut.

So on Tuesday I called customer service and talked to Sam and explained everything that was going on and she did not hesitate to make things right. On Wednesday I received a new Z axis kit and had it installed in no time, I did a test carve and it turned out perfect! I know this has been said many times before but there is really nothing that compares with the incredible customer service from our Inventables buddies! Thank you so much for your help and support @SamAlaimo, you really need a raise!

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I discovered the play in the z axis when the first pass and final depth of a pocket was not as deep as it was supposed to be. It appeared there was play between the acme thread in the plastic Delrin nut. The play appeared to be from both side-to-side & vertical. I ordered and installed a new Acme thread kit but the identical problem still exists. The nut at the top is tight and there is no play in any of the x axis roller wheels.

How do I know there is vertical in the z axis? I use a piece of paper to set zero. When the mill tip first touches the stock, I can manually lift the router about .020-.030" so I jog down .020" and reset zero and get a correct cut.

Does the whole acme rod lift when you do that lift test? Theres a nuloc nut at the top that needs to be tight. Ive also seen the delrin block mounting screws left loose or come loose overtime which results in similar to the described movement.

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