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Converting a Grizzly G8689 Mini Mill to 3-axis CNC, Part 14:



The last little bit of major fabrication to do, is the left end support for the X-axis screw. There's no real strain or support
needed here, just something to both close in the end of the table, and to hold a support bearing to the end of the
screw doesn't "whip" under high speeds.

The bearing is a tiny one salvaged from an old copier years ago, and has a 'snap ring' to form a flange
around the outside. So if I make a plate that that flange seats against from the screw side,
I don't need any real retention to the bearing, it'll be kind of self-captured.



So I bandsawed off a chunk of 1/2" by 4" aluminum bar stock, squared one cut edge, and eyeballed a likely location for the bearing.



That spot got drilled...



And then bored to accept the bearing, in a snug but slip fit.



Now, the problem here is that the screw is about an inch and a half too long,
so I had to redismantle the table, and remove the screw...



And then again wrap the ballnut and bearing with some paper towels and tape to protect them from gunk and swarf.



I then swapped the steel jaws with the bored-in-place aluminum soft jaws, again both for concentricity and so as to not mar the
ballscrew "threads", and slipped the assembly down the headstock so I could grip the screw up close to where it needed to be cut.



The "ball ways" of the screw proved to be harder than I expected, but with some carbide tooling,
I was able to part it off and turn an appropriate step in the end.



Then, using the aforementioned Heimann transfer screws, I marked the location of the bolt holes in the table,
drilled them out, and checked it for fit.



With the fit spot-on, I flipped it and counterbored the holes for the same 1/4"-20 capscrews used at the other end.
(Well, not the same ones, two more just like them.)



With that, I could degrease the plate, scribble on it with a Sharpie, bolt 'er in place, and scribe the profile of the table.



Then it was a simple matter of milling down to those scribe marks...



Which fits it a lot better to the shape of the mill table.






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