Z axis problem

[copperhead4321]

I Need advice on my Z axis? I was cutting a job on my shark pro yesterday and for some reason The Z half way thru the job took a real heavy cut, now the Z axis isn't working right it moves periodically after I move in x and y axis but not always, I thought I'd ask before I start taking apart. Has anyone had this problem? What might the problem be? The Z lead screw won't turn by hand, any suggestions would be appreciated.

[Jim N]

check for loose wire at connections or inside control box. "Seat" each wire in box - mine is just a friction fit in the slots. This fixed the same problem I had a while back.
Jim

[Tim Owens]

The first thing is to spray Silicon lubercant on the Z lead screw above the nut. Then move the Z axis up and down this will remove any contaminates that might be causing it to bind. Then if that still isnt working you can look at other issues. But this usually does the trick.

[copperhead4321]

I have finally got it to move in the +Z and -Z and just ruined a good board. It goes good for awhile then it seems to lose it's zero point in Z axis and plunges deep into job???? I will try the lubricant but I think it might be something else any other suggestions??