Tinkering is a re-skin of "Crafts". The intention is to separate the creation of a tool from the use of said tool.
Overcome: Crafts allows you to build, break, or fix machinery, presuming you have the time and tools you need. Often, actions with Crafts happen as one component of a more complex situation, making it a popular skill for challenges. For example, if you’re just fixing a broken door, neither success nor failure is interesting; you should just succeed and move on. Now, if you’re trying to get your car to start while a pack of werewolves is hunting you…
Create an Advantage: You can use Crafts to create aspects representing features of a piece of machinery. Creating Crafts advantages can also take the form of quick and dirty sabotage or jury-rigging on mechanical objects in the scene. For example, you might create a Makeshift Pulley to help you get to the platform above you, or throw something into the ballista that’s firing on you to give it a Jammed Pivoting Joint and make it harder to hit you.
Attack: You probably won’t use Crafts to attack in a conflict. Usually, weapons you craft are likely to be used with other skills to attack—a guy who makes a sword still needs Athletics to wield it well!
Defend: As with attacking, Crafts doesn’t defend.