Quote Originally Posted by John11668 View Post
While I bow to your experience Jazz, and I do know that my knowledge of this machine is limited to what I see on those pics . Never seen one in the flesh, Never used one.
But having replaced leadscrews with ballscrews in a different application, I found it no big deal , and it looks to me as if a BF on the outer end of the leadscrew/ballscrew would at least eliminate any end float in that screw without being a challenge to mount.
I dont see enough detail in the crosshead pics to know what is in there but it is hard to believe that an adaptor for a ballnut could not be accommodated. and £ 30 or so is not a massive outlay to keep the machine running reasonably while Petesos (like me ) continues his learning process.
No need to bow to me and all suggestions are good but that doesn't mean they are correct. This machine won't accept a BK type bearing easily and would severely limit the travels etc and the price is going to be much more than £30.!
As I see it without the tools to modify the end bearings to accept a ball screw designed for a BK setup the only sensible solution is to replace the screw with one that as been machined to the same end fittings, which is why I said contact Fred at BST. He will machine to any drawing you provide and at hardly any extra cost but it will still be much more than £30.
Other option is to do like been suggested and stick with lead screw and try to source one local.!

End of the day you have to decide how much backlash is acceptable. I would also question where the backlash is coming from because I'm sure I've seen +1mm mentioned and I'd be very surprised if all that is coming just from the screw/nut.? in which case replacing with ball screw won't get rid of that and that is my point about these machines. When you step down this upgrade path you open a can of worms with the only result being wasted time and money. It will always be a PIG with Lip stick on.!