Dwarves don't like magic spells.
Dwarves like magic items.
For dwarves, craft is everything, legacy is everything. What is a spell? A few words, some gestures, a flash in the pan. Ah, but craft something enchanted, and that will be around for ages. Can you pass a spell down to your sons? No, they are momentary recitations, stolen scraps of lore you don't comprehend enough to hold in your mind beyond a single usage. Does one forget how to swing a hammer, or wear a helm?
Dwarven magic-users do not adventure, for they have no need to purloin the knowledge of their craft from others. They learn it over centuries of dedicated study and tradition as firm as the mountains from which it came.