This is my first instructable. I was bored one afternoon when i was off college so i decided to make a scalpel and share how i did it. I'll have to warn you though, before i continue: this thing is as sharp as you make it. I also blued mine, with nasty toxic bluing solution. Be safe
Step 1: Make and Mark the basic shape
I snapped off a piece of carbon steel hacksaw blade aboout 3 inches long, that's 10 CMs. I chose a piece form the end of the blade becasue it's got a hole in the end, and that might come in useful for something. I used a marker pen to mark the bits i wanted to grind away. My camera's not that good, so you can't see that I marked the teeth of the blade too.
Step 2: Grind the shape
Using a bench grinder (sorry, but I couldn't figure out how to add steps of the tools and stuff you'll need. It's all here, though but you have to look for it. Sorry.) grind away the marked bits of steel. You should grind the curve of the blade, remove the teeth and grind a hollow for you finger to go into. The finger-hole thing's not really needed, but it's good to have it. Really it's only the blade you need to pay serious attention to, you can make the rest of it to your taste.