300 is safe.
I recommend testing acceleration values if you’re comfortable doing that if you feel you need more.
The best config change I made was the acceleration. I have to be watching to see any 3D Z movements like for 3D tabs. It’s just smooth. I’m going to do a 3D carve soon and should really see the difference.
Finally, I got a “best upgrade ever”. With delivery and taxes paid almost twice 
Tried to install it - have some issues how to “free” motor, and now, I got another issue - the rod is 3.5 mm taller than expected.
So - what is better - to use washers, or to cut the motor rod for that 3.5 mm?
Zip cut your motor shaft. Inventables use nonstandard nema 23 because of the pressed pulley.
I cut mine too for my z axis.
It’s an easy fix!!
Their shaft are longer than a typical nema 23 motor, most N23 shaft are ±.75" from the pilot or ±0.81" from the other frame. The pilot is ±1/16" thick.
**This is only for some with the pressed gear.
You can google it.
well the first winter upgrade begins…My “best upgrade ever” arrives tomorrow.
for the first time something for my xcarve will come from my own country, no surprise costs, no duty or tariffs and no waiting for clearance at the border.
Can wait to see how much this improves my cnc world lol
Loctite alll the screws!!
8"… wow. How much higher are you bumping your X and Y plates??
cncNewbie?
Phil,
So now it’s 8" travel?
Will that require dust shoe modification as well?
I rolled my own 
(Designed for a higher gantry, current config dont allow much Z-travel)
Ball screw (1605) and MGN12 rail/blocks for lift plate. Super firm 
If you guys have not notice I do believe Phil is turning into Dr. Frankenstein, (from Young Frankenstein because I love that movie) and his X-Carve is his Monster!!..lol…
@PhilJohnson resist the urge to build your monster a mate.
The devil is in the details 
I’ve had my newbies z axis for a couple of months now. I have the older wide version.
This past weekend, I was using the machine a bit and all of a sudden, I now get some stuttering in a certain spot on the z travel. It only happens going down though. Going up is buttery smooth.
I did notice that this plastic piece looks split. Not sure if that is normal or not. Anyone know if this is supposed to be like this?
Thanks for any insight.
I had mine apart. That looks like a failure.
I think you don’t have the same Z axis, I saw on an other post your nut seem to be with a spring instead split and o-ring. You have the one on linear bearings? If yes, your nut is different!!
My .02$
CNC4newbie himself responded to my email and says that that nut is supposed to look like that.
He is suggesting I check the 2 flange bearings and maybe loosen the lock nut on the bottom.
Thanks, I do have one that has a spring in it.
Install done, it was dirt easy…changed the GRBL settings as well.
Just have to figure out a simple way to mount the dust collection rails back on…I’m thinking I’ll trim the inventables ones, drill and thread a couple holes in them and the back plate for the X axis wheels then screw them down that way…oh and yes…blue Loctite
That’s what I did, I drilled and cut the brackets to size and then drilled and tapped holes in the carriage. Worked great, carriage is aluminum so drilling and tapping was easy enough…
