T8 leadscrew issues


I’ve just added the new T8 leadscrew and coupling and have the latest MPCNC813_GLCD_T8 firmware.

My issue is when I set a depth of cut to say 1.5mm, the Z axis usually starts off

Ok. Then after a little while the Z axis gets deeper then 1.5mm and begins to cut through the job, not lifting above the work.

I have tightened the coupling and grub screws.

My previous threaded rod worked great.

Any help would be appreciated.

Simon S

Make sure you have a look through the basic page again and set the max rapid speed no more than 8.4mm/s, if that is good make sure the whole thing moves up and down by hand very smooth and easy, did you lube it?



Hi Ryan

Thanks for the reply. I’ll check the rapid speed and I haven’t lube the screw yet,



Start with lube or the steel will chew right through the brass.

T8 leadscrews can have different pitches, I think (not sure) common is 2mm. I just got a 1mm pitch leadscrew from china by accident. Please check.

Unfortunatly even the vicious1 online shop doesn’t tell what size is sold, or what is configured in the MPCNC-marlin-firmware. I guess it’s 2mm. Maybe you have something else.

I sell 4 start 2mm pitch, 8mm/rev.