The problem with that is...And i know, cause I have the problem...
Not all printers print 1:1 ratio. I have to mess with mine, with the part, to get the correct footprint. I have to print something off, then use calipers to find the right percentage to scale down the output of the print. (or scale up)
For instance, create a 2inch x 2inch box, then print it off, measure with calipers, then adjust the print-out by a percentage until I get that 2 inch square box to really BE 2 inches.