How are the truss rod channels made?

[Hotzenplotz]

Very interesting, thank You!

So the grain of the filler strips is parallel to the frets?!
OK, that grain is with the moving direction and protects more against torsion of the whole neck, right?

Is there any special "guitar voodoo" about the channel? Is it just a simple radius or does it need a special profile?
I read that the p-bass uses a radius of 249" -unfortunately I can not find the soure anymore.

[Colonel Sanders]

Very interesting, thank You!

So the grain of the filler strips is parallel to the frets?!
OK, that grain is with the moving direction and protects more against torsion of the whole neck, right?

I would guess the wood grain would be parallel to the fingerboard plane as the new way to build the 2 pieces neck is to use quarter sawn pieces of wood with the grain running perpendicular to the fingerboard.

Which just made me realise if the new neck construction type can be one of the reason I really enjoyed my 2011 4003. I found it was sounding more ''post 1971 4001ish'' than all my other 4003.