bearings and ballscrew dont fit each other

[marbles]

Correct!! It must be that one side of the vernier jaws is out as I have to reverse them to measure the inside and out. Thanks for all the advice, much appreciated.

A bit of emery and on the bearings went. Worth asking the question thought as i'd not done this before and I didnt want to jam them on.

I wonder now if the retaining nut with the grub screw at the top of the twin bearing unit is enough to hold that lot, would a second nut be useful and if so where can I get one in the UK?

[Gary]

Cheap verniers are renowned to be inaccurate.

[JAZZCNC]

Defiantly will be the measuring. You can not accurately measure internal dimensions using verniers, you can't really accurately measure the shaft with verniers you need micrometers for both.

But like Jonathan says your using the wrong bearings any way so do your self a favour and get the right ones. They still won't fit if shaft dimensions are off but they will be correct for when they do.!