i devised a clever way to gget compound radius whithout block sanders or big jigs!!
i dont know if someone thought of this before, is so simple it hurts...
check this out:
i took a plywood base of about 50 cm long..
over it i place an thin mdf board (3-4mm thick) and screw it to the base along the center line..
then i stick thru the sides, between the mdf and the base, some 3mm sticks like this
by movin the sticks closer or away to the center you can control the radius on each side independently..you could even have compund radius as the lowers strings has one radii and the highers strungs another!
i got 10" and 16" on mine (on first and 24th fret resp.)
some pics of the process:
the 16" side:
the 10" side:
after double sided taping sanding paper on and started sandig the radius