Moving the ballscrew, whilst not disastrous, hardly gains anything. All you're gaining is some protection for the ballscrew from swarf and there are plenty of other ways to do that - for example adding seals or bellows. So even if the difference to the overall machine due to the loss in rigidity is small, you're doing this to correct a problem which is also very small since it's clear that swarf on the ballscrew is also only a small problem. I recall Jazz saying he'd worn out his ballscrews from letting the swarf pile up on them over a few years, but I've not come across anyone else who has had a ballscrew (or nut) fail for that reason.

Quote Originally Posted by Swarfing View Post
For this type of build it will work absolutely fine. Have a look around the forum with such a design and ask how they are getting on ;-)
Having the ballscrew on the back on my machine has crippled the stiffness of my Y-axis and although the distance is greater, that shows how the effect can be significant.