In article ,
Andy Hall wrote:

That was one of my concerns - if there is a lot of backlash, or
worse still a tendency to move, it would be a bit useless.
I suppose that some replacement of screws could help.

I have a cheap X-Y vice that was bundled in with
this Warco pillar drill. Faults are......

The clasp nuts are only fixed with nasty little grub
screws going into threads cut in the cast iron.
No matter how much I heave on these screws there
is still a tiny slop in the clasp nuts.

There is a slight slop between the lead screws and
the clasp nuts. There is no means (like a locknut)
to tighten this up.

The grub screws that key into grooves in the lead
screws and stop end-end movement need to be very
tight, so much so that movements are hard work.

The jaws of the vice are very slightly off with
respect to the X-Y movement. It means that when
I mill (say) a slot in an aluminium plate then
it is not quite parallel with the edges.

That said, even with all those faults, that X-Y
vice has done some seriously good work, doing
quick rectangular milling jobs, holding-safe
material that can snatch (Brass!), etc.

I've probably knackered the headstock bearings though.

--
Tony Williams.