Here’s a chain mortiser I picked up recently. These things aren’t too common these days, except for timber framers who use portable ones that clamp to the beam you want to cut a mortise in.
This is an older model stationary mortiser with a 2 HP 220 volt motor. It’s very powerful and can hog out these through mortises in a 2×4 in about 20 seconds.
The mortise this mortiser cuts is too long for cabinet doors, but it will work well for full-sized doors and for heavier joints in furniture. With today’s joinery options, you don’t need to use old-fashioned mortise-and-tenon joints to make strong furniture, but in terms of decorative appeal for certain styles, the through-mortise this machine makes can be very useful.
It can also make a stopped mortise, but the mortise does not have a flat bottom.
While this machine is certainly less versatile than a hollow chisel or slot mortiser, for what it does it is wicked fast.