Share 'Any way to flatten a maple fingerboard'

I am doing a neck with stick reset on a 1928 National wood bodied Triolian.  This guitar came to me with a previously stripped finish and missing tailpiece. Otherwise in structurally sound condition however with very high action though no obvious sign of structural deformation. It occurred to me that this round neck guitar may have been set for lap playing at the factory, though unlikely and I wa…