Roton Ball Screws - End Support?

[Docmani]

I've been lurking here for a while. I'm in the process of gathering materials for a DIY CNC router table. (Note, this is a repost from the DIY Router forum. I posted there, but I think I was asking this question in the wrong place. Mods - Feel free to delete the other thread)

I've looked at a lot of threads about the ball screws and nuts available from Roton and they definately look like they will do the job for me. My problem is that I have no access to a decent lathe to do the end machining for the screws.

Is there a poor man's alternative to properly do end supports for the ball screws and mount a motor, or do I need to save my pennies and go the homeshopcnc.com avenue and get it done for me?

I don't have any pre-concieved design for the end supports, so I'm wide open as far as suggestions are concerned.



FYI - Backlash is my main concern. I'm looking at doing detail work on prototype materials such as machinable plastics and/or machinable wax.

[ger21]

Originally Posted by Docmani My problem is that I have no access to a decent lathe to do the end machining for the screws. Is there a poor man's alternative to properly do end supports for the ball screws and mount a motor

When you say "properly", technically that would mean turning the ends on a lathe. But there are alternatives. I turned the ends of acme screws with a router table spinning a grinding stone. Mad a fixture with bearings in it to rotate the screw and slowly feed it into the stone. I removed a lot of material with a disc sander first. A similar jig/fixture with an angle grinder might work as well.

You can by support blocks from a lot of places, http://www.misumiusa.com/ is probably the cheapest you'll find.

You said that backlash is your primary concern. Imo mounting the screw without backlash should be relatively easy. You'll have a much more difficult time removing backlash from the ballnut, unless you'll be using double nuts.

[Mike Nash]

Your best bet is to find a new friend with the machine tools you need to get this done. I'd bet there's someone fairly close that would be glad to help. Maybe post your locale with a question about who could give you a hand? While I would help, I'm in Alabama, not Maryland. I'm also no machinist, though I have some of the tools to be one.

Also be aware that one end of the screw(s) Roton ships is possibly (probably?) annealed for a short distance already. Look for a slightly brighter area at one end. The rest seems to be through hardened and not just case hardened. If I had known this initially, I would have ordered mine as three pieces, not just two with one to be cut into two. But the annealed length was pretty short on mine. I just ground the hard end into a nose (turned the softer ones) and made a stub shaft with the necessary bearing fits and threads and shrink fitted it on. This way, if I "screwed" up I could make a new end out of cheap cold rolled instead of buying a new screw.