Spline Jig

https://www.woodpeck.com/spline-jig.html

Strengthen your miter joints with Woodpeckers new Spline Jig. A normal mitered corner lacks the long-grain to long-grain contact needed for a strong joint. Since it isn't completely end-grain to end-grain, it will usually hold together for a while, but it's weak and probably won't survive seasonal changes. You can make the joint rock solid and add a design element at the same time by adding splines across the miters. Woodpeckers Spline Jig makes it simple to add splines to all kinds of mitered joints using either your table saw or router table. Just set the stops to position the cut where you want to add a spline, drop your pre-glued miter project in the jig and make the cut. Glue in the spline and just that quickly, you've made an attractive joint that will last for generations.