Hi masterbinky, thanks for your comments about vibration, I'll add them to HaDe's list and take care of paying attention to them. Anyway, the most notable vibration issue was the loud noise from the steppers and now they are gone when I changed print speed to a higher value (lower than 20mm/s it start vibrating) and acceleration that I had it all at 0.
caffeinatedsoap, I also bought "non calibrated" rods and got the same sloop when inserting the 6mm bearings. I took a time here in Spain to find a decent place to buy the rods, they are not difficult to find and provably you are able to find them at a local store but always ask for "calibrated 6mm stainless steel rods", from that they may ask you about mate or bright, alloys, etc but all of them will fit perfect.
caffeinatedsoap, I also bought "non calibrated" rods and got the same sloop when inserting the 6mm bearings. I took a time here in Spain to find a decent place to buy the rods, they are not difficult to find and provably you are able to find them at a local store but always ask for "calibrated 6mm stainless steel rods", from that they may ask you about mate or bright, alloys, etc but all of them will fit perfect.