Rotating Ball nut

[drumsticksplinter]

Hi Everyone,

This is my first post on here, so please be gentle...

I'm building an 8' x 4' router and have the rolling framework nearly complete. To cut a long story short I bought a 'kit' from someone who had bought the linear components, motors and spindle separately. I wish now I'd just done the spec myself and ordered everything myself....

The machine is here:




For the X axis I have 2 x 2510 ballscrews x 2800mm long with ballnuts, however, I found out that they are slightly bent as is the 1500mm long 2510 for the Y axis... I think I can get out the bends with a garage press so I'm not too concerned with that. My concern lies with the whip I'm going to experience with the long ballscrews. I'm building this machine to cut woods and plastics for prototyping and small production runs. I calculated that the maximum rapids I'll get on the X is under 150 IPM, which will do my head in waiting around all day for it to cut anything... So I'm now looking at the revolving ballnut concept!

Has anyone got any simple but tried and tested designs for a revolving bullnut. I've got large nema 34 steppers and pulleys for a 2:1 reduction.

I've already seen this:



It looks a very nifty idea, but I'm open to other designs and also looking for someone who could machine me the components please.

Many Thanks in advance