[shepdog]

Well, an abundance of free time over the holidays has rekindled my desire to cnc my mill...it is a round column mill, made by craftex:

http://busybeetools.com/content/prod...uals/B1977.pdf

I have read as much as possible and think I'm set to start ordering parts, but my first outstanding question is this: when ordering the ballscrews, how can I determine the proper length, factoring in the machined ends, mounting blocks, etc? I had planned on ordering from linearbearings2008 on ebay, who kindly gave me the specs for a Rf31 mill, but I am not sure how close my mill is to that.

thanks for any thoughts,
steve

[Bubba]

Steve,
Back when I converted my RF31, one of the first things I learned (the hard way) is that you can't count on dimensions from two different machines to be the same. This especially goes for hole placement locations. As much "fun" as it is, I highly recommend taking the table off and doing your own measurements taking into account the factors you mention. Its really not that bad to do and after the first time it gets mostly easy. Just don't drop the table on you foot:})

Good luck and look forward to your build thread. Let us know if we can help.

[dracozny]

using the X axis as an example I measured the length of my table and then using the dimensions of the ballnut for the size screw I wanted I determined the amount of over travel I needed to keep the same length of travel I have. Then I factored in the bearings and oil seals for both ends, Do not forget the threading for the nuts(you want the bearing mounted area to be a tad short so the nuts will hold the ballscrew firmly, some might say this is your preload, some might not. Finally factor in the length needed to mount your gears or couplings, it's a good idea to give a lil margin for error on this end. Go over your drawing a few times to be sure you have it all measured right.

If you do oil seals you will have to make bushings for the seals to ride on, otherwise it just wont work.