This has probably been asked a million times and I'm probably missing the reference somewhere, but can you take 10 or take 20 on a craft skill?
lastgrasp
There should be no reason that you couldn't Take 10, if you don't need a really high score. It makes sense.
Taking 20, however, shouldn't work. When you Take 20, you're assuming that at some point you'll fail, and eventually get it right. But any time you fail when you craft, it uses up costly materials. Literally, Taking 20 assumes "no penalty for failue" in the Rules, which is not the case for a failed Craft skill check.
Take 10, yes (unless someone has abducted you and has you craft at crossbow point).
Take 20, probably no.