no don't do that... using the .0015 feeler gauge:
you put the straight edge on top of the feeler gauge, pushing on the straight edge lightly, with the straight edge aligned as in the diagram...
If you pull on the feeler gauge and it comes out easily, then you have a low spot greater than .0015 at the location of the feeler gauge
If you feel a slight tug, then the low spot is about .0015, which can be acceptable in some cases.
With a level surface, the feeler gauge requires a hard tug to be removed from under the straight edge. Just be sure that the straight edge is perfectly straight (true).
Keep lifting the straight edge and move the feeler gauge to locations along the straight edge.
If I say straight edge one more time it'll be rediculous... straight edge
okay sorry if I sound like I'm trying to be a teacher or something.. you probably know most of this
and yes, I see what you're saying if you can fit a .010 under the straight edge, then you've got warpage... you might even be able to see it from the side
