For production, look at a big router, a guide bush and letter
For quick hacking, a Roman or Engraver font (originally designed to be
chiselled) and an Arbortech (disk in an angle grinder) will work, but
it's quite skill dependent. Arbortechs are _not_ the same as those
evil chainsaw circlets. They also do a carbide tipped version, that
might be useful for osage orange.
Die Gotterspammerung - Junkmail of the Gods