Disassembling X-y Table On Partial Cnc Converted Mini Knee Mill

Steve Shannon

Rocketgeek
H-M Supporter Gold Member
Joined
Nov 27, 2015
Messages
603
Last week I scored a Harbor Freight 40939, mini-knee mill which had been partially converted to CNC by replacing the lead screws for x and y axes with ball screws. In order to move it into my shop I want to remove the table from the knee to save weight. The head was removed when I got it. Here I have it strapped to the loader to move it.
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Unfortunately I screwed out the lead screw and now I have a bunch of small balls in a cluster. It was one of those "oh no!" moments.
How do I safely separate and remove the tables?
More pictures:
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Thanks!


Steve Shannon

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Last edited:
I was successful in removing the X and Y axes, leaving only the knee casting. How I did it will almost certainly come back to haunt me though. I couldn't get the bearing holder nut undone at the end of the X ball screw and then it began raining. So, I did exactly what I did on the Y axis ball screw and unscrewed the screw from the ball nut. I put four little supermagnets (I pull them off of worn Sonicare toothbrush heads) into the hole to attract any wayward balls, then plugged both ends with wads of paper toweling to retain the balls.
I discovered something happy though. These ball screws are NSK brand, which I am hopeful means that they are good quality and that they will be easier to put back together. I still have to get the base with the knee on it into the shop, but I'm getting closer.
 
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