T8-8 vs. T8-2 Leadscrew?

One of you smarter guys maybe can answer this. Seems I got a T8-2 Leadscrew from eBay in my ignorance. Was causing me all kinds of issues with my Z axis until I figured out it was moving 1/4 what it should. Anyhow for my MPCNC does this matter or not?

To be safe you should reduce your Z feedrates by 4, especially the rapids, because otherwise (after adjusting steps per mm) the speed (RPM) of your Z stepper will be higher and at high speeds comes less torque and possible missed steps.

I have noticed Estlcam (and possibly others) use the Z rapids feedrate to go up at the end of a cut, and the ordinary, slower feedrate to go down into the next cut. Higher speeds are that much more likely to skip steps, even without gravity, and if your tool gets progressively deeper then a mere ruined workpiece is the best possible outcome.


Also, it’s probably a better option to reduce your microstep setting under the driver by 4x than to increase your steps/mm by 4x in the firmware.

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Since I was curious about it from another thread, I did some research. It seems the skipped steps during higher speed on stepper motors isn’t lost torque but rather magnetic fields generated that oppose the direction of motion, and require higher voltage to overcome. Whether it’s a linear relationship or not I’m not certain (I didn’t get too far down the rabbit hole) but using a higher voltage power supply (24V instead of 12V for example) means higher speeds on the steppers without step loss.

Yes, but you can also hit the step limit of the cpu on 8 bit boards.

Right, but reducing microsteps helps with that I believe.