One of my all-time favorite hand tools is the router plane. However, I very rarely use it to create joinery. In my shop, its sole purpose is fine-tuning. The blade can be set at a fixed distance from the base so it is incredibly effective at creating dados and grooves of a consistent depth.
When I cut dados in large boards or plywood, the pieces inevitably lift up to some extent. The scary thing is you might not even realize it’s happening. But when you go to assemble the case, you can’t figure out why the sides are bowing out! Chances are, your dados and grooves were not cut at a consistent depth. Enter the router plane! I make a habit of setting my router plane and quickly going over each and every dado in my projects. You’d be surprised at how much material this bad boy catches, and the subsequent headaches it can prevent. If you don’t already have one, you should definitely pick one up! They’re so choice!