I'm using a large Bosch router to finish 2 inch deep mortises and pockets with no problem.. This is in green Hemlock with a 2.5" cut 1/2" dia cutter. But I do two 2.5" drilled holes and a circular-saw edge cut where possible, and often chisel out the big chunks. The finish-up is about 30 or 45 seconds.
The MAIN thing is that the jig holds very close tolerances on final dimensions and the fit is excellent every time without fussing..
Even on big straight-cutout half-laps in 8by8 timber I use the router and a jig just making a 1/2" deep cut. There is almost no tear-out cutting with an electric chainsaw and a perfect guide for the cut every time. I do have a jig for holding the chainsaw nose on each half-lap cut, though, and that makes an accurate cut right down the routed line pretty easy. I smooth it a bit with the chisel to make myself feel good. But I probably digressed!
There's an interesting subject of jigs and tooling that I'd like to get into some other thread. Then there's the pickup-truck crane...
