Type of ball nut

[ptjw7]

Hi All
I am considering buying some ballscrews to put on my little X1 milling machine and are getting a bit confused as to the type of ball nuts on offer.
The only difference I have seen apart from increased cost is the amount of backlash in the ball nut.
The 3 types I have seen are:-
1.0 as is about 0.04mm backlash
2.0 Preloaded with increased size balls( unknown backlash)
3.0 Preloaded with a spacer (again unknown backlash but costley as it uses 2 ball screws)

So considering that I am replacing a fairly grotty chinese screw thread will the first ball screw (also the cheapest option) be OK in the long run or just hang the expense and go to preload.

Peter

[Oldmanandhistoy]

Hi Peter,

I have just very recently ordered some ballscrews and nuts from here http://www.homeshopcnc.com/page3.html . I am using two nuts/axis to make an adjustable zero backlash setup.

Hope it will be of some help to you,
John

[toastydeath]

Preloaded ballscrews shouldn't have any backlash.

Personally, using a machine without backlash is well worth the cost involved. I'd look at the two options and try to determine what the other features involved were, as I'm not familiar with a functional difference in preload methods aside from ease of adjustment. There should be more features that cause the price difference, not just preload mechanism.