"ss" wrote in message
...

I dont use chisels much, so much so that over the years I didnt realise
how bad they had become, also the stone was hollowed out. What I did for a
quick improvement was use a piece of flat pack wood and glued a few grades
of wet & dry to it. Not perfect but a vast improvement on my chisels, now
looking for a piece of plate glass. I use the eclipse guide, its ok for me
as I am not sharpening chisels every day.

Plate glass is not float glass and may vary in flatness.
You can always grind it flat if you want.
Its easy to do but you need three pieces and you grind each one against the
others in a sequence that makes all three flat.
Its how you make optical flats for telescopes.

It used to be how you made engineers flats except you used a dye marker to
indicate high areas and scrapers to actually remove the material.