Cutting a rule joint for a table leaf or extension takes a bit of skill and some precision, including the use of cove and roundover cutting bits and likely a few passes, especially in harder woods.
By matching a 1/2″ cove-cutting bit to a bearing-guided 1/2″ roundover bit, you have everything you need to form a classic rule joint. Test your setup on scrap stock of exactly the same thickness as your table top and leaves. Use multiple passes to achieve your desired cut — especially in hard maple.
Combining two router bits and some hinge and screw hardware allows you to make a clever and attractive rule joint as seen in this layout.
Locate and mortise in your rule joint hinges, and you’ll be well on your way.
