For item creation, you'll need ritual(crafting) as a bare minimum. It will grant you the ability to create enchanted items and potions. Each enchanted item or potion needs 1 enchanted item slot, or more if you want to increase their strength and/or frequency (number of uses per session). After that, you'll need refinement, which will grant you 4 enchanted item slots per point of refresh.
You could also go so far as to "invent" a new power, basically renaming ritual(crafting) and use craftsmanship instead of lore for creation purposes. That would mean you know less about magic and the supernatural in an academic sense, but you know how to make use of it in a practical way.
Now depending on what exactly you want that hammer to do, you can go a few ways about it. The easiest would be to treat it as a focus for your crafting, if it is only supposed to help you with your crafting. You can get 2 focus item slots for one point of refresh, and the maximum focus item slots on any item can be no higher than your lore skill. You can raise either power or frequency in this way, depending what you like. A mix is a good idea, in most cases, I think.
The next thing you could do is to treat it as an item of power. That's kind of tricky, since that would mean putting your crafting ability into the hammer, so without the hammer, you would not be able to create anything. As a focus, you could still craft, only a bit less powerful.
I am kind of on the fence for putting refinement for focus item slots and enchanted item slots on an item of power, since I feel that is double dipping. If the crafting ability is on the item, too, I might have less of a problem. YMMV.
I kind of see an evocator and an artificer as diametrically opposed. The evocator uses his power on the fly, to create numerous effects, but he is limited in what he can throw around at any given time. The artificer on the other hand needs time to create his items and plan things out. But his attention to detail and the time he invests in his workings mean, that he can be much more precise with his intended effects, and even more powerful.
Creating/Changing items and their properties on the fly would be something I would use sponsored magic for, since it allows for "thaumaturgy at evocations speed and methods" (often called evothaum around here, for short). With sponsored magic, you would also get a type of evocation and a type of thaumaturgy, that fit the magics sponsor. In your case, your ancestors could be the sponsor, and using the magic is channeling their accumulated wisdom through the hammer.
Hmm, I hope that was more helpful than confusing. If I have raised more questions than answered them, just ask away, and I will do my best to clarify.
