Z Axis Tweaks

First of all, Happy Father’s Day to all of you who are fathers.

Today provided me some time in the shop to play, so I decided to tram the cnc.
I set the x, y, and z axis square, and using my laser as a pointer on the wasteboard, decided to recalibrate as well. You know, normal maintenance… (ha! yeah right! Normal…)

As I finished the X and Y axis, and was moving to the Z to double check everything, I noticed an issue that has been bugging me since the X Carve was built.

The Z axis was always a bit sluggish, and made weird noises when moving up or down. I was never able to really tighten the Delrin nut completely, and this always bugged me as it would allow slop and play in the axis. It also caused the Z axis to hang up in tension at certain points in the range of motion.

After a very thorough inspection of the complete z axis assembly, I noticed that my acme screw was slightly tweaking forwards and backwards at full travel.

I took the Dewalt carrier off of the axis, and started measuring the Delrin nut. That’s when I found the issue!

It appeared that the delrin nut was threaded slightly canted from back to front!

I removed the nut, flipped it over front to back, and re-installed it onto the carrier, figured what the heck, and really torqued it on this time.

I re-trammed the carrier on the axis, put everything back together, and lo and behold…

All noise is now gone.

My delrin nut is tight as it can be.

The slop in that part of the z axis is gone.

This made such a huge difference that after re-calibrating (again, due to the z axis change) x, y, and z axes, I was actually able to boost my travel speed of the Z axis to over 1500 mm/sec!

Nothing yells at me when the z axis moves any longer, and the acme screw seems to be much much happier.

If you have had issues with your Z axis similar to mine, or find that your z axis cuts too deep or too shallow, I highly recommend that you try this tweak.

My stock Z axis now has a new lease on life until I can afford to upgrade to the CNC4Newbies Z Axis… (this will be done now strickly to gain Z height to match my Triquetra Y axis plates)

I will update this thread for those that care once I get a few carvings under the belt as she sits now, but I can already tell that I can increase my feed speeds way more than before now…

Has anyone else ever come across this before? I’m not sure I’ve ever seen a post on this one.


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