How would I go about checking them (lead screw) for accuracy?
If you have a 1" indicator you would just take any backlash out and then set the DRO and your indicator to zero, then, make say .050" moves
in one direction and see how close each move is to the indicated position. You can plot deviation from the norm is so desired.
Then go the other direction and see what happens. Don"t be suprised if the lead varies on one side of the screw as compared to the other.
On this end I have a 40X optical alignment scope with optical measurement capability to .0001" and use a calilbrated scale so measuring quickly along the screw ( even to 36" length ) is easy for me and thus i can profile the complete screw without resetting anything.
RICH