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Hi, I've put together a basic mill platform (x-y) based on this page: http://www.pathcom.com/~vhchan/cnc/cnc.html

My table is a bit bigger, so I have about 10 x 6 travel using 1/2-10 ACME rods and acetal leadnuts (Delrin). So far, I'm in the 25 IPM using geckoes on this and the same motor as on the guy webpage. Hey, I had them on hand and they were the biggest I had, kinda lucky. It has spider couplings and ballbearings as thrustbearings. Play is less than 0.002.

Now I really wonder how to do Z cause if I use the round column, I end up losing 4 inch of travel as I'm not in the middle of the table.

Since I need to put the head forward a good 2 inches, I was thinking of a 2" square tube on a base and then some horizontal spacers at 6" and 20", then a vertical 3" x 1/2 cold rolled rail with the carriage being bearings sandwich in aluminum plates and then fix the original drill spindle head on it with all proper modifications and addition of the angular contact bearing on a new shaft.

Here is a pic of the base. I'd just like to have some ideas for Z. I'd need about 12" of travel. I'm not too sure about the forces in question. Do I need to preload a bit, a lot? Is 1/2 inch enough understanding it's the cheap drill head that goes on it? Can I use rolleblade bearing there?

I'll mill some alu, a lot of delrin and a bit of steel. The plate sure would be better than a round column.


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