Amce screw/Anti-back lash nut?

I've been looking around for a lead screw for my soon to be built
router CNC machine.

My X-axis will be around 3" and will be an gantry-style machine. The
gantry will be riding on roller bearing on edge of a piece of 1/4" x
2" CRS. I found a place (www.pic-design.com) that sells an Acme lead
screw and anti-backlash nut. The part numbers are #ARS4x3708 (36" $52)
for the lead screw and #ARN24-3708 ($24) for the anti-backlash nut.

This lead screw is 3/8-8 .5 lead 4-start (stub). Would this be
sufficient size for this router table I am building? Is the .5 lead
the dist it will travel with one revolution of the screw? If so, is
this a good choice?

I was quoted the prices above, If I bought the 36" and wanted to cut
it to make a 12" piece for my z-axis, What is the best way to cut this
lead screw? A regular hacksaw? What about the ends, do I need to have
the ends machined to hook-up a pulley system to the steppers? Would I
need to have both ends attached? What about mounting options? Any
tips, ideas, comments?

Thanks to all those that reply.