New TBI Ball screw - How not bent is enough? & How to test?

[Bongo]

Hi all, so we got some new TBI ball screws from Fred at BST Automation, to replace the bent 5mm pitch ones - as discussed on the forum here: http://www.mycncuk.com/threads/14508...r-build-pickle

I have given them a little examination and there's a problem:



As far as I can tell (and please do let me know if my measuring method is all wrong) one screw has a wiggle of 0.35mm and the other 0.15mm. The nut's flange seems very accurate as does the motion of the nut relative to the screw.
So my question is how realistically straight should they be??? This is with the v-blocks about 1.8m apart, and the last ones were over 1mm out over that length... Would it be reasonable to expect the x rails and bearing attachment to push the TBI screws straight during use with this level of run-out? Or should I be contacting Fred to query this?

They were not super cheap, and before I go ahead and modify the rotating nut attachments and fit them I would really appreciate any feedback you might have.