moving table engraver

Hi,

Been putting off making of a fixed bridge-moving table
engraver/router of acceptable precision (for engraving). Been looking
a the hardware shop for some supporting/guide rods and found some
16mm round steel bar. They look reasonably round. Wondering if I can
use them for the 2 support/guide rods for the x-axis moving table for
a movement of 24 inches which means the rod will have to be 48 inches
long.

Will they be sufficiently round and straight for the purpose that I
have mentioned (for engraving, not precision metal working). If so,
will two milled holes of very slightly bigger diameter in delrin
serve sufficently as support bearing for the x-axis moving table? I
have access to desktop cnc lathe and mill.

Thanks for any input.

Andrew