Okay, I'm not sure I'd call this a bug, but either something is wrong or whoever made this really made it so if you have the upgraded forms of the clockwork arms you don't get the achievement. Can this be changed? If it's really what's going on it's kind of silly...
The clockwork axes come with enchantments when you tinker them, but I think the achievement works as long as it's called that. If you put it through an anvil, I believe it no longer works (I haven't personally verified that second part)
I believe he's talking about having overclockworked power arms instead of clockwork power arms. Which I could easily believe would break the achievement.
Yeah, I ended up making Overclockworked Power-limbs before I had completed the rest of the set, and now I don't have the achievement even though I have dual clockwork axes, a clockwork bolt-thrower and two overclockworked power-limbs...
