Seems like we have two separate issues in this thread. The OP wanted to know ow to cut slots in ribs and formers, not hinge slots. Maybe he should have said notch, or maybe I misunderstood his question. If he is looking to slot control surfaces for hinges then the GP hinge slotting tool is the way to go. I make a shallow starter slot with a Higley hinge slotting tool to guide the cutting blades and follow up with the GP tool. Very fast and accurate and no need for jigs or any other types of guides.