Hi Th2c! I usually just use the regular handles since the fancy ones don't really increase your profit by much. But I tested out making both copper and iron great hammers with fancy two hand grips and everything worked just fine for me. Which version are you currently playing (the latest update is 0.0.72) and are you making the hammer heads with 2 or 3 ingots? Thanks!
(edited for grammar....twice, sadly)