mounting ballscrews onthe ol mini mill help

i have just recently purchased some warner electric 3/8 inch
ballscrews and nuts and am trying to figure out a way to mount them
in my mini mill without extensive mods to the mill(mainly because i
dont have anything else to machine it with!)

im wondering if i absolutely have to use thrust bearings when i
mount them to the table or if i can use good quality precision
bearings ,if held firmly on both sides?
i mean, how much axial force is really going to be put on the
bearings with a mini mill anyway?
i ask this because finding thrust bearings to fit this ballscrew
after machining the ends down to 5/16ths or so is looking to be
impossible. i can find precision bearings all over the place that
would fit snuggly on the ends.
and i think that if i enclose the bearings just down to the
ballscrew with the motor mounting plate on both sides, that this
would work.

any ideas or suggestions from you fellow CNC'ers or knowlegable
people out there??
thanks for the input if any.

K.S.