Thank you for your replies…
I try to insert the link to my video.
youtu be/3qgXVnRpJ5k
My setup: table dimensions 2500x1250
control board: ramps (bought on amazon)
firmware installed: [V1ZXY_Ramps-2.0.9.2.zip]
no endstop
I’ve made all the wiring following the guide on this site.
Z motors connected on the same connector on the board.
I’ve used this wiring
www v1engineering com/wp-content/uploads/2015/10/IMG_20151022_112457.jpg
Actually I’ve tried with:
- change the strength of the screws
- check the perpendicularity of the pipes
- loosen the bearing screws
I would like to test the current with a voltmeter during the moving of the z axis, but I don’t know what pins I must check togheter.
I’ve read in the forum someone have replaced the power supply with a stronger one.
Actually I’m using a 12V 6A power supply…
for the link I’ve removed the dot from the addresses 
Thank u very much for your help
Pierluigi