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.

Step 3: Remove the Paint, Rust, Oil, Other Crusty Stuff.....

After you've ground the blade to its shape, you'll need to sand it down. This has 2 functions, 1: it removes the burrs (fluffed-up meta) from the grinding. I already forgot to tell you that when you're grinding, dip the metal in water every 2 seconds. If it gets too hot, it'll lose its temper and become too soft to keep an edge for any great length of time, and a scalpel's job is to cut. Soft metal won't cut well enough.
The second reason for sanding is to remove the paint from the blade. If you have ruined the temper, it'll probably show up here as discolouration. I used a piece of porous breezeblock (cinder block for Americans, I think) but fine sandpaper, of even a soft stone work just as well.

Step 4: Sharpen!

Back to the grinder. Gently stroke the bit you want to be the blade along the fines grinding wheel you have. Once or twice per side should do it, remember, the steel you're using is very thin, so will grind down very quickly. Watch that temper, there's no excuses. After you've finished grinding, start on an oilstone. You want to remove all the scratches from the grinder. Sharpen both sides of the blade. If you sharpen properly, you'll get a razor sharp edge, but you need to be patient. Sharpen as much or as little as you want. Sharp edges cut better but wear down quickly. Blunter edges don't cut as well, but last longer. Considering how thin the steel is, it's worth putting a REALLY sharp edge on. It doesn't take long....I think there's an instructable on sharpening somewhere.....You can't see in this blurry and nasty photo, but the sharp edge of the blade is fully formed. If you want to, stop here, your scalpel is complete and there's not point continuing. Don't do anything stupid, blah blah blah. For those so inclined, go to the next step.

Step 5: Bluing the Blade

This step isn't really needed, but i did it so the scalpel looks cooler, and won't rust as easily. Apply the bluing solution of your choice to the blade, and follow the instructions to get the best results. Once you've finished bluing the blade, sharpen the edge again. I'm not sure how bluing solution works, but i suspect that there's a little corrosion to form a skin of oxides on the steel. Sharpen the edge again to remove this layer. Be careful not to scratch the flat bit, otherwise it'll look shoddy and ameturish (not sure how to spell that) Congratulations, you've just made a scalpel, don't do anything stupid. If you've got anything pertinent to add to this, please comment. Thanks for reading through my needlessly wordy instructable, i'll have some more at some point.
just a thought: 3 inches = 7.5 centimeters
long before finding this Instructable, I hit upon the idea of anealing a hacksaw blade,filing it (no bench grinder!), and reheating and quenching it, made a pretty good little knife!
See if you have macro on your camera Use that and re-post pictures
If you're talking about a concrete/cement block with holes through the middle then yes that's a cinder block for us Americans.
you could use a hacksaw blade
ok, i am all for DIY, but this seems a little silly when you can buy high quality scalpel blades for £1.50 for 5...
dead for ages? why this instructable is good. Even if your picture aren't perfect, i get the idea. As long as you post new, better instructables that force people to look at your account, they're bound to look at your old instructables sooner or later.
man this is like AWESOME! use it for that one pvc pocket knife or sumtin, and have a cool knife! now i gotta get a grinder...
you know blueing solution contains cyanide or used to anyway but it appears to work by chemically 'anodizing' the metal I'm sure theres a better word but it dyes it in a similar manner from what I can tell
wow, i thought this'd been dead for ages, thanks for commenting! My guess is that the selenium dioxide content of the solution rapidly oxidises the surface of the steel. I've not seen any cyanide warnings on the side of the bottle, but i'm still not going to drink it.
the stuff I used was from my dad's old air gun kit It was a dirty harry revolver .44 magnum styled but you blued it with some kind of cyanide solution which was very effective but deadly also by the way i just happened upon this mini project and it reminded me of a simple block guillotine with a blade made of spring steel ground to a fine edge it had a slight curve and using the same technique shown here for sharpening an interesting slicer can be made
Nice job. When using tempered steel for blades (as saw blades tend to be) it's a good idea to reheat them to glowing red and let them cool slowly (rather then dipping in water) and resist the temptation to let them heat up too much (beyond bluing) and then rapidly cooling them. Tempered steels tend to be very hard but very fragile, great for saw blades, files and thick blades but very easy to break when sharpened to a fine point. This is also true for other tools made from saw blades (which are indeed a fine source for cheap steel) - reheating them and letting them cool removes a lot of the tempering (not as much as staring with untempered steel, but close enough) and makes them more flexible and less prone to snapping or cracking. They do become less hard, but a blade doesn't need to be since it won't be put through the sort of treatment a saw blade would be. We'd make knives out of worn out files in this way back in the day, reheat them and let them cool a few times and grind them into shape. It was always tempting to just go for it right off and to let them heat way up and cool them rapidly in water during grinding, but inevitably they would snap or become rather fragile knives at the end. I assume the same would apply here.
The reason i dipped it in water was so i didn't interfere with the temper. As you know, a scalpel's job is to sliiice things, and soft steel can't hold a cutting edge for as long, as you know. The sawblade was already plenty springy, so i didn't think i needed to do anything. I did consider tempering the bits that get the most stress so they were tougher, but decided against it, because it was just too easy to overheat the steel. Also, don't blue it: now it smells of cabbage
It's certainly not the worst idea - you do need some temper and it'd probably pan out ok. Saw blades aren't nearly as tempered as heavier tools, so it would probably go pretty ok. I've never specifically used saw blades for knives, so it could well be that removing the temper further would be worse then leaving it. Just thought I'd mention it since I've had good experiences with removing the temper prior to making tools out of saw blades.
As soon as i get the bits, i'm going to make myself a gas forge. Then i'm going to forge myself a knive from the wonderful steel that my old worn out files are made of
I just found this site and reading the conversation and noticed that you are looking to build your own forge. You should check out www.lindsaybks.com Dave Gingery the guy who started the company, which is a publishing company that specializes in reprints of old tech. man. and others also has a book set for less than $60 USon how to build your own metal shop -- from the forge in the first book to making your own metal lathe and so on using the forge to cast parts and such.
Files, levels, pliers, and all sorts of drop forged steel tools do often have material that would be the wet dreams of metalworkers in past centuries and provide it for cheap or free. I'm no great metallurgist, but many who have devoted a significant portion of their life to the study assure me I'm not deluding myself. I've only rarely worked with forges (as a child/teen my grandma had a gas fired one mostly used for ceramics I sometimes re-purposed, but I resign myself to a butane or acetylene/oxygen torch these days) but I'm sure it'd be good fun especially for someone with a more solid interest.
it's practically impossible to find the stuff as Stock, so i've taken to making things from stuff lying around, like barbeque tongs...and all sorts of other innocuous stuff
I know what you mean. Even though I'm not a huge tool maker, when I decide I need something I can't or won't buy it's like pulling teeth so get some decent stock, or even find what it is I ought to be using. It's a bit crazy that getting a tool made from it is cheaper then the actual stock it was made from, let alone digging a broken tool out of a dumpster or a trash pile at a machine shop for free, but that's supply and demand at work I suppose.
I'm toying with the idea of forging old chisels into usable stock. I reckon they're ABT 0.5 / 0.6% carbon, just right for a nice easy heat treat
I was actually looking in my brain for the word "chisel" when I was listing tools that work for knife stock - English isn't my first language. We made a few knives from them, just ripped the handles off, de-tempered, grinded and tempered slightly. It's been long enough that I'm not positive which ones were which out of our experiments, but I seem to remember they worked well. I hope it goes well, I've never really had that much patience. Metallurgy is much more art then science, though science plays a big part it's often counterintuitive and very much something that has to be "felt" rather then "calculated".
right, personal judgement is just as important as knowledge in doing this sort o thing. I'll add some more instructables of more sharp things i make as and when i make them. perhaps a letter opener next, I'm back at college the day after tomorro, tho, so it might be a while
ever hang around turkish prisons?
you like movies about gladiators?
Can you say "SHANK!" :)
Very clean and pretty blade, i think you could also anodize it :3. Nice job! Maybe you can even add a handle tutorial
Steel can not be anodized. Aluminum on the other hand can be :) Anodizing Al makes Aluminum oxide which, for Aluminum, is equivalent to rust on ferrous metals ;)
huge problems with missed letters.....i'll pay more attention next time.
you can still edit your instructable.
i know, but there's so many other things to do...i'll just go and find out what they are.....
Interesting. FYI, there is an Instructable about how to take close-up pix using a common or garden variety electronic camera, like I bought couple of years ago for $100. Take off your glasses and stick them in front of the camera, the camera will then focus 25 to 30 cm. I don't know who to credit, but I appreciate his tip.

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Bio: I shouldn't have to tell you that using a dagger to undo this little, fiddly screw's a bad idea. AAAAARGH! big project ^^ so ... More »
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