Timburr should learn wood hammer.
Should he, though? By the time Timburr reaches a level where a move as powerful as Wood Hammer becomes remotely reasonable, he’s not Timburr anymore. It makes sense for Timburr, sure, but in practice what we’re actually saying is “let’s give Conkeldurr Wood Hammer,” and… I don’t think there’s any good reason for that?
EDIT: Pansexualkiba adds: There are some Pokemon who have access to moves in their base form that their evolutions can’t get, though! Like, for example, Riolu and Force Palm or Nidorina and Poison Fang.
To which I would answer: absolutely true, but so what? Those are moves that still make perfect sense for Lucario and Nidoqueen.
Conkeldurr getting Wood Hammer would hardly be the stupidest thing we’ve ever seen in terms of move compatibility, but I think that not giving it to him is perfectly understandable.