How much force should it take to make the Z axis move when powered up? Kept loosing the zero and I thought it was belt skip or loose set screws.Tightened the belt almost to the point of bending adjusting screw. I removed the plate in front of the pulley and watched and the motor is spinning with moderate pressure in the vertical direction. Going to check wiring in the morning to look for bad connections.
More than the other axes ~20 lbs.:
I noted pitch here: http://www.shapeoko.com/forum/viewtopic.php?f=37&t=6765&p=53075#p53075