whene i press Z i can't sellect the hammer head or the shild and all the costumers want grate hammers and i can't craft

you can select when you have stuff on the anvil! It just does not show you that you did, just click what you want [if you only have one ingot you can not select blunt because blunt needs 2 ingots!]

so fix: put TWO ingots on the anvil then press Z