Y axis ballscrew mods

Like an episode of Breaking Bad, we join the action without any of the backstory. Unlike that fine example of episodic television, we may or may not understand what went on here by the end of these posts...

Given that the second-hand/surplus ballscrews that I found are worth considerably more than the mill itself, I decided to make a hole in the base casting to allow the Y axis ball screw to hang out under the column instead of cutting the excess length off the screw. Dry cutting the casting with a hole saw here as there is silicon in the cast iron. A precision machining operation! Slow going but you get there with some persistence and elbow grease.

Same thing for the front of the base casting:

I had to move the whole axis down to make enough clearance for the flange of the ballscrew. If I got the math and the measurement correct there should be about 30-40 thou to spare.

I also had to take the ballnut off the screw in order to assemble the axis. So I whipped up a quick ball keeper on the lathe out of some acetal rod. Finished diameter is a couple of thou under the minor diameter of the screw.

The keeper fits tight on the screw journal - then just unscrew the nut right on to it.

Most of the fabrication for the conversion consists of machining (rather tedious) bolt circles for the support and motor mounting plates. 

The Y-axis ballnut mount is a bit more complicated.

 Chucking rectangular stock in a 4-jaw - good video here: http://www.youtube.com/watch?v=a7HhppYHwig&feature=youtu.be

Finished part. Precision isn't astounding, possibly a few thou off, but then it doesn't need to be...

Now I just need some 3/4" rod stock to finish up the stand-offs for the X and Y axes.