Ballscrew or leave alone?

[John S]

Done a few WM16's and one thing to bear in mind is that some convert easily and some don't.
The stumbling block is the bed in the middle, the casting when being cast, sags and make the gap tighter in the middle.
No problem with the top, that's machined so no sag. From the ones I have done it's 50/50 if a ballnut clears.

So worst scenerio is to get someone with a big mill to take a lick out or angle grind a clearance grrove.

WM14 are usually OK, I haven't come across a bad one but WM 18's 'always' need machining