You should take a look at some engineered flooring sometime. I think it
would surprise you. Certainly a .010 clearance gap in the groove is way
too high; probably .001 is closer to it. A flexible material like wood
doesn't need the clearance gap that metal does. A manufacturing thickness
variation of .005 is way more than existed with my product. The variation
from the tongue/groove to the surface is the thing that matters (not
total thickness). I'd guess it was probably .001 or less, virtually
undetectable by touch.

Thanks for the feedback. I would expect close tolerances for all
pieces from the same box. I am surprised that they can hold .001"
tolerances in wood. I agree the .01 tolerance for clearance would be
excessive. I am use to injection molded engineering plastics which
usually are not held that tight. I guess you learn something new every
day.