I have been wanting to come up with a good solution for breaking down vegetables (or whatever) for cooking. I have a food processor and a mandolin, so I've got the slicing, julienne-ing, etc. under control, but it's hard to get to that point sometimes - things don't always want to hold still to get cut. I've seen all the cutting boards with clamps and whatnot, at least online, but they never seemed like a good solution. In my book, your food-holding hand is actually doing a more complex task - holding something soft or slippery firmly but without crushing or bruising it. So I decided I just wanted a knife that would hold still, and anything I could accomplish by moving said knife, I could do by moving the food.
I have a good friend who is a model-maker and last weekend we went to his shop, where we cooked this up:
we bonded this piece of plastic to a cutting board I had...
so you can rest the knife in it...
and then another piece to clamp it in place with two screws. except i already lost one...
and the result is, you have the most dangerous cutting tool i've ever seen in the kitchen. which is one reason we made it so that i could take it apart. it also makes it easier to clean, and to store.
here's a view from the top, so you can see how the two pins hold the knife in place, although it's also clamped by tightening the screws.
and a shot from the opposite side.