Official Luthiers Forum!

You would likely assume wrong.

While marble and or granit flooring tile is often polished ground, It is not necessarily flat. is is likely to have a valley to it. Now we are talking in the thousands of an inch but depending on how worn the polish stone it was ground with was at the time. You can not count on a specific piece being flat to with in a couple thousands in a foot.

I would not want to use Marble much more unstable and porus than granite. I could find a truly flat piece of granite floor tile I might use it, but if granite floor tile or counter tops were flat why do you think QC departments would pay $1k+ for precision ground granite inspection tables in stead of buying a granite counter top.

I have been able to find about 3"X4" hunks of phenolic at industrial scrap houses. this suff is stable and won't warp. Boeing processes make for lots of cool scraps in this part of the country. I've flattened the phenolic on a granite surface plate and then use 320 stick-it on that. The frets should be fairly level to start if the board has been prepped well before the fret went, then its just a little kiss on the tops of the frets to get any high spots dealt with.

I am told Glass is the material of choice for flat. It's the method used getting level with glass that causes problems

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CRAIG LAWRENCE of AUSTRALIA
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