Hope that piqued everyone's interest.

There was a Norton 4000/8000 lapping question recently where Randydance mentioned that he checked a newb's DMT 325 grit with a straightedge and the plate was NOT flat. That got me thinking in a concerned way since I have a DMT 325 & a new 1200. I took both to a pal's machine shop and we laid them both on a grade A pink granite surface plate.

Long story short, both the 325 & 1200 were about .001" off. The 1200 was .001 higher in the center (convex) and the 325 seemed to have a .001 slope upward.

It's been said that .001" or less will not affect honing a razor's edge. It's also been said, and fervently believed by many on SRP that taping a spine, for bevel setting, etc then removing the tape for polishing is a bad bad idea since the removal of the tape lifts the edge off the hone by the width of the tape which is enough to prevent polishing of the edge thereby accomplishing little (think of the tape as a shim. Removing the shim lowers the spine but raises the edge OFF the hone).

So........How thick is a piece of black electrical tape? How thick is scotch tape? If the thickness of tape can interfere with the overall honing process (unless the tape is kept on the spine from start to finish), is a tape's thickness dramatically far off from .001"??? I wonder. I have no micrometer to check, but maybe one of us does?

Why do I bring this up? What do I want to find out? I want to know if in fact .001" variance from flat will have absolutely no effect on honing a razor (this assumes the razor is flat). Maybe I'm making a mountain out of a mole hill, but I'd like to know.