Take the plunge-with a router
A jig keeps the edges flat
This mortising technique calls for routing a slot in 1/4"-deep increments. In addition to a plunge router, you'll need a sharp bit -- we recommend upcut spiral bits -- and either an edge guide or jig to keep the router bit within the layout lines. You can eyeball the start and end points of the mortise, or clamp on stopblocks to limit side-to-side travel.
Whether shop-made or store-bought, a router-mortising jig, like the one shown, proves a versatile addition to any shop. You can easily align the clear acrylic top's scribed centering lines to workpieces. When making a jig, cut the mortising slot slightly longer and wider than the actual mortise to allow for the offset between the bit and the guide bushing that rides in the jig slot.