Ball screw sizing and machining

[mpictor]

I have a geared head, round column mill/drill and a 10" Logan lathe (model 200?) that I want to convert to cnc.

I intend to use rolled ballscrews. What size do you recommend? I'd like to use the same size for everything, but I'll probably have to use something smaller for the lathe's X axis due to clearance.

I'll machine the ends myself if it's not too difficult. I remember seeing a site explain how to chuck the screw using BB's and a piece of tubing, but I can't find it. Can someone point me to a good description of the process?

Everyone talks about angular contact ball bearings. What about tapered roller bearings?

If anyone has converted one of these machines before, advice/drawings/pics/etc would be appreciated.

Thanks
Mark

[Bubba]

I would use the "5/8" inch ball screw as they are the lest expensive and are adequate in size for most of our applications. I used them on my round column RF31 several years ago and am planning on using the same size on my 12X36 lathe.

[mpictor]

Originally Posted by Bubba I would use the "5/8" inch ball screw as they are the lest expensive and are adequate in size for most of our applications. I used them on my round column RF31 several years ago and am planning on using the same size on my 12X36 lathe.

Yeah, I saw the 5/8" ones were significantly cheaper in McMaster, so I was leaning that way.

I forgot to ask: what brand(s) would you guys recommend?

[Bubba]

On my mill/drill, I use Roton and on my lathe, I got a stick of Thompson to use.

I think this boils down to a Ford/Chevy debate on which one is better. What matters more is what precision you want (remember, better precision is spelled $$$$$$$)