The CNC router table at my local Makerspace has a vacuum hold down table. This is nice for larger boards, but smaller pieces of wood do not have enough surface area to hold down by suction alone. I built this jig to hold down smaller pieces.
Step 1: Route T-Slots Along Board
Metal T-slots are available, but I wanted to use something sacrificial to avoid damage to the router or the bits if they inadvertently hit the tracks. They sell a T-Slot router bit at rockler that was able to make these.
Step 2: Add Grip Surface
I glued a wood strip along the bottom edge of the jig to give the piece something to hold against. To give it extra strength I added grip tape to make sure the piece wouldn't move. I haven't had a slip with this jig.