I made these two rabbet planes by replicating a larger 17th-century example. The main characteristic is that they each have only one open side. For the blade, I used a file, properly shaped and sharpened. The body is made of mahogany, with a wenge sole. The metal bar on the side prevents the body from flexing when the wedge is tightened and adds weight to the plane. You could avoid this by either increasing the thickness of the plane body or reducing the width of the blade, but both would be uncomfortable compromises.
The hole for chip ejection can easily be made with a Forstner bit. The body design is very close to the original, and I must say, the finger support is perfect.
Since each plane only works in one direction, you need to make two twin planes, each for one direction. One use I’ve found particularly convenient is finishing rabbets. In one instance, when I made a rabbet with a circular saw, the blade setting was off, and it left a visible step. That was an easy job for one of the little twins!