When I saw this machine in the Woodsmith magazine last year I knew I had to build it. It uses a router motor, and I just happened to have a Porter Cable motor in a fixed base just sitting on its duff and not earning its keep, so it was a perfect fit. Using a brand new set of spiral upcut bits, it can do 1/4″, 38″, and 1/2″ mortises. What this machine gives is the clean walls of a router cut mortise, plus the visibility and ease of set up of the hollow chisel mortiser, and does it almost twice as fast. Does this mean I’m getting rid of my Delta Hollow Chisel mortiser I’ve had for over 20 years, not on your life.
The field tests are continuing, but I am very pleased with the results so far. For those who worry about the rounded ends of router cut mortises, you may relax. First off it only takes a couple of minutes to round over the tenons (there goes the time you saved cutting the mortis), secondly I had a brain storm the other day that I have yet to try, but will soon – use this machine and the hollow chisel mortiser together. A square hole at each end of the mortis then use the new machine to quickly mill out between them. Cool, huh? I’ll let you know how it works.