If you only have a few mortises to cut, you can always drill overlapping holes and remove the ridges with a chisel. But for projects that need a lot more mortises than that, the chisel method quickly becomes unmanagable.

That's why we designed this versatile mortising tool that you can build yourself - at far below the cost of purchasing a conventional power mortiser. It uses a conventional hand-held router and a spiral (upcut) but to cut the mortises. It's quick and accurate, making perfect fitting mortises every time. This woodworking plan appeared in Shopnotes magazine No. 47.