Andy's bread board is another useful tool. He writes, "My neighbor made it for me. I just bought a decent knife that has a straight edge that can be sharpened. There is a small 1/4" hole drilled in the end of the knife and a 1/4" pin in the backboard that it rotates on. I cut potatoes, fruit, and other vegetables with it. I do keep the edge very sharp and have yet to cut my finger. What the guy who made it for me did was drill two 1/4” holes in the back board pieces. Then he just ran a cut off 1/4” pin through the knife and into the opposing 1/4” holes in the back board pieces and then screwed the back pieces to the cutting board. Another thing that helped was he made a shallow saw cut in the cutting board where the knife lined up. This helps the knife go completely through what you are cutting." The board can be made from hardwood or 3/4" exterior plywood. You could also buy a laminated hardwood cutting board and use that for the base. The back is made of two pieces. Before they are attached to the bottom board two 1/4" holes are drilled in one end of each of the back pieces at the same height which is predetermined by the hole in the knife. A part of a cut off 1/4" bolt is then placed through the hole cut in the one piece, the knife placed on the bolt and then the other back piece is placed so the bolt goes into the predrilled hole and then it is screwed into the bottom board. If using hardwood, screw holes should be predrilled using a bit slightly smaller then the screw's diameter and countersunk if necessary.
The knife you select must meet certain criteria. First of all the edge of the blade must be flat and second is it must have a squared end as opposed to a tapered end that comes to a point. If you look at the picture below and to the right, you can get some idea of what I mean. You should be able to find one on line.
Please note that the plans shown are not to scale.