Giovanni's Workshop is all about the Gadget Shoppe. We receive this quest as soon as we complete Giovanni's Stilling the Rumble quest. Note that the first two objectives are exactly the same as those in Magnus' Ye Olde Gadget Shoppe quest. However, completing them in tandem will only get you so far; you'll need 8 or more brass ingots, total, to complete both quests and the ones that follow, so there's no reason to worry if you don't have both quests at the same time.
Once you finish this quest, you are given Tinker Time, also by Giovanni.