Ball screw load ratings

I'm in the process of choosing a ball screw (or lead screw) for a CNC
retrofit of my mill/drill. Can anyone suggest a value for the maximum
axial load such a ball screw would see? I would think only 100 lbs.
or so, but I really have no idea.

If the value is low enough I can use a modified acme screw with an
anti-backlash nut (up to 125 or 250 lbs. depending on the style) and
will save much $$. Otherwise I'll have to go with a ball screw and
preloaded nut.

Thanks,

Jeff

PS - FWIW, I'm looking at the Kerk NDB series lead screws - they're
only 53% efficient but very inexpensive relative to ball screws.