I purchased my K2 machine used a few years ago, and it has preformed well since then. Yesterday I was milling the recessed seat area for three rocking chairs, and I every so often with the first couple of seats, it would periodically cut a few thousandths deeper. Not so much but enough I will have to sand a bit to smooth the area. When I got to the third seat, the machine did the same thing but then the spindle stopped moving even though Mach3 just kept sending instructions. Something had caused the machine to bind and knocked the reset.

At this point, I wasn't sure which axis was causing the grief, so I checked that all the mounting screws were tight, and that all the belt pulleys were tight. No issues. So I changed my code to run parallel to the Y axis rather than the X axis. Part way into the program, the machine skipped some steps then later stalled again. At this, I was feeling the issue had to be with my Z direction, so I pulled the spindle and unhooked the controller motor. The spindle bracket slid easily up and down the assembly. I couldn't feel any spots of extra resistance or binding. I removed a few more brackets to expose the ball screw. When I ran the motor to raise and lower the spindle mount, I noticed a pretty good wobble at the bottom end of the Z ball screw, maybe about 1/16" or move of movement. The Z ball screw is only anchored at the top of the Z assembly, and the table end just floats.

https://youtu.be/IrV84djodew

I was surprised to see this much movement in the ball screw, and believe it might be enough to cause the axis to hiccup or stall during a micro move command. I am not well versed with these machines as I never built this one and have only done routine maintenance on it. I am hoping someone here can offer some insight as to whether this is likely the source of my issues. If so, where is the best place to get a new ball screw assembly? K2 is no longer in business.

The ball screw may have been like this since I got the machine. I mainly cut inlays and do Z level milling, which minimized the Z movements or moved the Z in larger increments. With the chair, I had a lot of very fine Z movement. Or maybe I damaged the ball screw when I moved the machine. I'm not sure. I'd just like to get the problem fixed.

Thanks for your help.

Ken