Sorry about the extreme necro-post. But coming across entries like this in unchained makes me wonder
"Create armour spikes or sheild spikes without craft (armour); (skill) blacksmithing; (DC) +5"
And
"Create wooden armour or wooden sheild without craft (armour); (skill) carpentry; (DC) +5"
So it appears that you can use some of the broader crafts to make more specific items its just the DC's go up.
