A trim router isn’t a panacea for every routing operation, of course. Big bits and deep cuts spell trouble with a tiny router, so use common sense. Still, you can cut rabbets, dadoes, laps and other joint parts with a trim router, the same way you would with larger tools. Run the edge of the base against a clamped straightedge; install an edge guide or use a piloted bit to limit cutting depth. The key is to take reasonable cuts so you don’t overwhelm the motor or the bit. I used a trimmer to cut all of the back panel rabbets and shelf dadoes for a small cabinet to store cans of finish.
The cuts turned out every bit as accurate and crisp as if I had made them with a dado blade or my mid-size router. Would I use a trim router for cutting joinery on every project? No. Three-quarter-inch through dovetails? Forget it. Nada on deep mortises, too. I would choose my bigger routers, router table or some other method for safety’s sake on tough jobs like these. But, some joinery can be cut with a trimmer. Give it a whirl.