"djs" wrote in message
oups.com...
This sounds like a good idea. However, I would like to get a flat
reference surface a little larger than this. The 9x12 could handle my
14 inch number 5 Jack plane, but I will needs something a little larger
for the longer planes. Do you know if these granite surface plates are
actually certified flat to a certain tolerance?


Get a piece of glass. It's flat within the size of the finest grit you'll
be using to lap the sole. If you're using paper, which has no thickness
standard for either the backing or the thickness of the abrasive, MDF on
your TS will be fine.

Essence of lapping, after all is getting to an _average_ by keeping things
moving.