Has any body out there used hardware from this outfit.....
http://stores.ebay.com/linearmotionbearings

They advertise their ball screws as C7 and they certainly look ground, from the photos.

I'm curious just how they are getting the "anit-backlash" features in their ball nuts, as their 16mm nuts only measure ~1-3/4" long (with the flange). Is that long enough to get two seperate tracks? Or are they likely just oversizing the balls?

Limited experience here.....