Custom jig for Mortising

I don't have a dedicated mortiser, so for making mortises in legs or rails I usually make up a custom jig from medium-density fibreboard. I then use a plunge router with a template guide and a 3/8" or 1/4" spiral upcut bit to cut the mortise - the Freud 75-106 3/8-Inch Diameter 2-Flute Up Spiral Router Bit [amazon] is usually my bit of choice.

The jigs are quick and easy to make, and ensure that all the pieces have the mortise or holes cut in the exact same place. The top picture shows the underside of the jig.

The left jig in the photo is for cutting a mortise in a stool leg. The leg blank is clamped between the two inner supports, the outer supports are just there to stabilize the base. The mortise is then cut out with the plunge router in 2 or 3 cuts depending on the depth. In between cuts I use a shop vac to clean the sawdust out of the mortise.

The right jig is for drilling a series of holes in a rail that will then accept vertical slats. Using the jig makes sure the top and bottom rails will match perfectly.

I make sure to label the jigs with measurements and try and reuse them whenever possible.