Knife making

Posted by: Bear Cavalry

Knife making - 10/12/09 12:21 AM

So I found this site a while ago, and figured that this project would be perfect for the light weight section. I have to admit, even when I am trying to pack light, I will splurge for a knife a little more heavy duty than this.

Survival Knife

Another project on his site that is a favorite of mine, I have not yet gotten around to making one.

Khukri Overhaul

He has a lot of cool knife projects on his site.
Posted by: JimmyTH

Re: Knife making - 10/12/09 02:33 PM

The kukhri looks good but I can't imagine how the hacksaw knife would be useful for much. Hacksaw blades bend too easily, stock's too thin for a knife and the temper is wrong.

I used to make a lot of my own tools and knives, cutting blanks from plow discs and sawmill blades and shaping by forging and grinding. Getting things tempered right isn't easy and the thinner the steel the trickier it is. One of my favorite knives was built around a blade blank of laminated swedish steel, all I had to do was make everything else, bolster and handle slabs and pommel and sheath. Still lots of work but it was a really good knife and I've still got it someplace.

I looked for the blade and Woodcraft Supply still has it at Woodcraft Supply Large Laminated Knife. I had a few pieces of Brazilian rosewood laying around back then, and the blade I used had a rattail tang, so I wound up with a really nice looking knife with a rosewood handle and brass fittings for about twenty bucks. Heck of a deal. Price has gone up on the blade now, but it's a full tang model, stronger and simpler. Several other kits available at Woodcraft Supply.

Posted by: Bear Cavalry

Re: Knife making - 10/12/09 04:05 PM

Yeah, I kinda feel like the hacksaw blade is just to small/light to be very useful, but I figured somebody in the the market for really small lightweight gear might find it useful.

I am looking into getting a Kukhri right now, I think that will be a little more useful, and I am willing to haul a little more weight for a lot more usefulness. I made a pretty good little blade out of a piece of a big lumber saw, used some pieces of antler from my attic to make the handle, I don't know where that is anymore...somewhere.
Posted by: phat

Re: Knife making - 10/12/09 04:10 PM

I've seen M40's site for a while. I agree with his sentiment on chopping - at least when it comes to "high impact" type camping/survival or winter stuff getting firewood. Personally, I've used knives like the kukri, but when it comes down to it for chopping, give me a regular sized knife and then for equivalent weight a small 1.5 lb axe. the smaller knife is then better at doing knifely things, and the axe is far better at everything else. If you want a nice one go find a gransfors forest axe, or the little fiskars axe..

Now making a sheath for the axe and putting a little kit like his survival kit on it might be ok. but this is all stuff I always have in my daybag anyways, anywhere I go.

Posted by: Spock

Re: Knife making - 10/12/09 09:32 PM

Nicely put, Phat:Use an ax for chopping/splitting. A small knife will do "knifey things" better. A 2" blade takes care of cutting line, tinder and food packages. A 4" blade is useful for cooking, marginal for splitting and useless for either chopping or trimming toenails. And if it is a good chopper, it will not be much good for anything else.
Posted by: JimmyTH

Re: Knife making - 10/13/09 12:36 AM

I agree with the chopping concept, if you have a knife big enough for that it's a clunky hatchet. I think the Kuhkri was originally made as a sort of combination machete and short sword, sidearm in the Indian or Pakistani armies. The camp knives you get here are mostly toned down versions. It's not really meant for the uses we favor.

I always carry a knife style knife, and I take a light tomahawk, a custom single bevel type I talked a smith in Montana into making for me. I know enough about smithing to know he's a lot better than I am. Haven't regretted that, you can chop with a knife but the tomahawk works. By the time you start on something with a knife, the tomahawk is finished already. No contest there.

Posted by: Bear Cavalry

Re: Knife making - 10/13/09 01:03 AM

I see what you are saying about rather having something especially made for the job, but it seems like (depending on what you are planning on chopping/cutting) there could be a middle ground that would save you packing an extra tool. I know that a small to medium kukri won't do the job that a hatchet will, and a large one won't cut like a knife, but I think you could probably manage with a middle sized one, and spare yourself the weight of the second tool. While I am not a hardcore enough ultralight fan to worry about the weight of an extra knife, there might be some who do. In the end, I just think that they are dang cool knives that are fun to use. I realize that it may not be grounds to add it to the kit, but I will at least play around with it.
Posted by: finallyME

Re: Knife making - 10/13/09 10:43 AM

I think you need to test out your theory. Use the Kukuri on a bunch of knife jobs that you think you will need to do, and then do a couple hatchet jobs with it. Make sure to post your results.

Anyways, I lost my train of thought. It's that dang bear doing backflips.
Posted by: Bear Cavalry

Re: Knife making - 10/13/09 01:54 PM

I plan on doing this eventually. I will be sure to post the results up here. At present the only kukri I have access to are old ones that my grand father got in WWII when he was stationed in the Pacific. I am thinking I probably shouldn't tear those apart.

I am looking at a couple different possibilities to purchase, around $20. The Cold Steel model supposedly was pretty good, but then they switched suppliers and the steel is crappy now and will not hold an edge.

I freaking love my dancing bear.
Posted by: Jimshaw

Re: Knife making - 10/13/09 11:25 PM

Ditch the bear or I'll never read your posts
Jim crazy
Posted by: phat

Re: Knife making - 10/14/09 02:17 AM

At least the bear isn't wearing a kilt wink
Posted by: bigfoot2

Re: Knife making - 10/14/09 10:13 AM

Originally Posted By phat

At least the bear isn't wearing a kilt wink

That would be SWEET!!!!!!

BF cool
Posted by: Bear Cavalry

Re: Knife making - 10/14/09 11:54 AM

If I can find one, I am putting that up. Kilts are cool...especially if there is a breeze.
Posted by: bigfoot2

Re: Knife making - 10/14/09 11:11 PM

Originally Posted By Bear Cavalry
If I can find one, I am putting that up. Kilts are cool...especially if there is a breeze.

Told ya' AGAIN, Phat lol Don't be "Kilt hatin'" lame

BF cool
Posted by: Kent W

Re: Knife making - 10/24/09 08:53 AM

Bear, My high school shop teacher taught us that a old file makes the best knife blade. You have to take your time grinding it to shape so it doesnt get to hot. A knife blade made in this fashion will hold a edge better than any I have seen. Files are very high carbon steel. Todays knives are all shiny pretty Stainless. There are some hard Stainless blades out there. 440 Stainless makes a respectable blade. Happy Trails!
Posted by: Pika

Re: Knife making - 10/24/09 09:18 AM

My high school shop teacher taught us that a old file makes the best knife blade.

Like a lot of old time legends, this is true to an extent. You can make a knife out of an old file but it certainly is not the best material for a blade. File steel is compounded to be hard when tempered; it is about 1.5% carbon. Hard steel such as that will hold an edge but unless the blade undergoes a differential tempering process it will be extremely brittle. Most files are brittle; at least more brittle than is desirable for a knife blade. Grinding a knife from a file retains the brittle nature of the file in the knife blade. Annealing and tempering are required to produce a reasonable knife from file steel; or any carbon steel for that matter.

IMO, the best carbon steel for a knife blade is that used for saws. It is about 1.0% carbon, can be hardened to hold an edge but still retain the toughness (lack of brittleness) that makes a good knife blade.

I am convinced that if one wants a knife that will hold an extremely sharp edge, it is hard to improve much on good carbon steel. But, if you look at the steel used in surgical instruments, it is almost always some type of stainless. Modern stainless alloys can hold an incredible edge but not one that will hold up to the types of use to which a pocket or sheath knife is intended.
Posted by: Knight Hawk

Re: Knife making - 10/24/09 05:25 PM

batman and the shark is better, you should use one of the bear cavalry pictures
Posted by: Kent W

Re: Knife making - 10/24/09 07:59 PM

What do you use a knife for a screw driver or to cut? Brittle yes but sharp yes again. Knives are for cutting not prying etc. So brittle doesnt matter unless you are trying to cut a nail in half like on a tv demo!You will not break afile knife boning a dear or cleaning fish. Pry the lid off a can of beans instead of using can opener? PERHAPS!
Posted by: Bear Cavalry

Re: Knife making - 10/24/09 08:42 PM

Got the knife today, it is a beast. Put an edge on it (it came dull). Going to need to modify the sheath because I went ahead and tore the leather off. It seems like they used some sort of water soluble dye to blacken the leather, so that was no good. I have yet to go out and test it, but it is dark and I have to do some philosophy research.

I will probably put photos up at some point.
Posted by: Pika

Re: Knife making - 10/24/09 10:14 PM

If you want a knife ground from a file, great, get one and enjoy it. But, I think that most established custom knife makers know more about knife steel than did your shop teacher. And, I don't know any who would make a blade from steel with 1.5% carbon; they would go bankrupt from all of the broken returns and grinding them to shape would take months. Perhaps your shop teacher had had experience with older files that had lower carbon steel. These days, those who make blades of carbon steel use saw steel, not file steel.

If you look, you'll see that most files are 1/8" to >1/4" thick; they need this thickness for the strength to withstand the flexing to which files are prone when in use. Most knives are no thicker than 3/32" and are often 3/64" thick or less; if you had a knife this thin made of heat-treated file steel it would snap like a potato chip the first time it was even mildly stressed. To have any strength at all, a knife of file steel would need to be thick and heavy.

Check it out; Google knife steel. You will find that most knife makers who use carbon steel use something like 1095 steel; 1095 is 0.95% carbon. It will heat-treat and harden quite well and take a long-lasting edge but is still tough enough to withstand some flexing. Ka-Bar knives are made of 1095. You are right that a knife is not a pry-bar or screwdriver but the blade has to be able to bend a bit. And, brittle does matter in a knife. Hardened file steel is more like glass in its flexing ability; ie none.
Posted by: Kent W

Re: Knife making - 10/25/09 09:26 AM

The only knife blade I have seen bend a bit was a thin fish fillet knife. When cutting as intended they do not bend. But enough. My intention was not to get you upset!
Posted by: finallyME

Re: Knife making - 10/25/09 03:52 PM

If you use a file for a knife, you have to temper it so it doesn't break, like Pika is trying to say.

Here is a video that shows how to make a knife from a file. It also explains why you need to temper it.

Video 1 Video 1

Video 2

Video 3

Video 4
Posted by: Tango61

Re: Knife making - 10/28/09 12:03 AM

Originally Posted By Pika
IMO, the best carbon steel for a knife blade is that used for saws.

Pika, what type of saw blade? I have several old 7 1/4 in carbon steel circular saw blades and have considered cutting the up to try knife making?

Would this be okay or should I use an old carbon steel handsaw?

Posted by: Pika

Re: Knife making - 10/28/09 09:05 AM

A lot of the circular saw blades are alloy steel that is chosen to minimize warping when they heat up, or to provide a good bond for carbide teeth. Most of them are good steel for knives but since the composition is often unknown, you could spend some time experimenting to find the proper heat treating method. Alloy steel can be tough to grind as well.

The hand saw, if it is more than 20 years old, is most likely good carbon steel, probably around 1% carbon. I have never, yet, had a problem making a knife of handsaw blades. The blade will be a bit thinner than that of many knives but often the thinner blade will be easier to grind and keep sharp.

It is extremely important to keep the blade cool when you are grinding. A grinder with a water spray is not essential but it will speed up the grinding process by a factor of ten.

Also, if you have a steel supplier nearby, you can order 1095 steel in a variety of strips, sheets and bars. That way, you can have a blade as thick as you want. Costs though.

You might want to look up some information on heat-treating carbon steel. If you heat-treat properly, you will have a tough blade but one that will fiercely hold an edge. You will want one that covers annealing and hardening. I have some references on the subject but they are down in my shop building. If you would like, I'll send you the author and title once I get down there. Just let me know.

Have fun, it is really satisfying to use a knife you made yourself.
Posted by: finallyME

Re: Knife making - 10/28/09 09:23 AM

Originally Posted By Tango61

IMO, the best carbon steel for a knife blade is that used for saws.

Pika, what type of saw blade? I have several old 7 1/4 in carbon steel circular saw blades and have considered cutting the up to try knife making?

Would this be okay or should I use an old carbon steel handsaw?


Tango, I have actually started to do exactly that. I found an old 7 1/4 circular saw blade laying in a field. I decided to see about making a knife out of it. First I annealed it in a fire. Then I cut it out of the blade and shaped it with a file. Now I need to heat treat it. It will be a very small carving blade, so maybe no tempering. I will post pics when I actually finish it. I have been taking pictures of the process along the way.
Posted by: Kent W

Re: Knife making - 10/28/09 08:12 PM

Pika what is the mehod to heat treat a saw blade? I have treated mild steel shafts bye heating to a straw color and burying in a can of powdered lime. This greatly slows the cooling process. Havent broke one yet but havent stressed one to terrible either. As for treating a file to make less brittle would simple annealing help?
To all those reading, I sugested a file for knife making because most people have a old small file around. This makes it a inexpensive way to start. Hard and Brittle, yes as Pika says . Good practice in begining knife making? I think so, with care they can be servicable, Best maybe not ,but servicable.
Posted by: Pika

Re: Knife making - 10/28/09 09:32 PM

Heat treating is both a science and an art. The first step is to harden the steel. To harden, one takes the annealed, formed piece and heats it to what is termed the critical point. This is often described as a "cherry red heat" but it differs for various steel compositions. The best way to determine the critical point is to heat the steel until a magnet is no longer attracted to the hot steel. Then, you quickly quench the piece (here we are talking about knife blades) in a liquid.

The best liquid to use for quenching is often a matter of dispute. At one time, sperm whale-oil was highly regarded. I use SAE 30 motor oil. Others use a stiff brine. Basically, the quicker the steel is cooled, the harder it is. Brine is used for files, it produces a super hard steel. Using oil will slow the cooling somewhat and will produce a quenched steel that has a bit of toughness. When quenching, it is important to plunge the knife quickly and straight into the quenching liquid. Hesitation or lack of a straight stab can cause the blade to warp.

Once you have quenched (and hardened) the blade, you are ready to heat treat. There are two ways to do this. One is to carefully heat the hardened blade to the temperature stated on the specification sheet to produce a give Rockwell Hardness. This requires an oven and accurate temperature control. The entire blade will be the same hardness and toughness using this procedure. Most commercial knives are done using this process and it works pretty well.

The method I use is called differential hardening or differential tempering and is done by "running the colors". You don't need an oven or thermometer; I have a coal forge and use that. You first polish the blade to a good shine. Then, you heat a bar of iron in a forge (or charcoal fire) to a red heat. You then place the back of the polished blade on the hot iron and watch the colors develop. What you are looking for is for the first straw color to just reach the cutting edge along the full length of the blade. This takes a bit of practice because you have to move the knife blade around to push the straw color ahead in places and hold it back in others. You do not heat and let the straw color reach the edge and then quench again, you let the colors move slowly across the blade and stop by themselves. Ideally, when you are finished, the bulk of the blade will be blue, about 1/8" of the edge will be straw and the other colors will be compressed between the blue and straw. When done this way, most of the blade is springy; springs are tempered to blue. But, the edge with its straw color is just a bit softened from the hardened state with a bit of toughness. Steel with 1% carbon heated to a faint straw will hold a fine edge for a long time.

I probably used up a dozen forged knife blades before I got adequately good at differential hardening. I still screw up on about one out of five blades. That is one reason I like carbon steel like 1095 or good saw steel. Unless you get it hot enough to burn the carbon out you can re-harden and try again. I would sure hate to have to do a sword this way though.
Posted by: Kent W

Re: Knife making - 10/29/09 09:27 PM

Thank You. I am going to try a small knife this winter. That brings back a bit of memory. I have several old carbon saw blades. Even a couple of 28 inch sawmill blades. Im going to try your method! I Cut and Pasted your instructions and printed them as well.
Posted by: Ecrow

Re: Knife making - 11/23/09 09:51 PM

Pika is right about steel stock. So here is the compromise: buy a sawzall blade that you like, carefully heat it until it loses its magnetism (cherry) and let it cool off slowly. (insulated). Then work it into your shape but don't fully sharpen the cutting surface or it will burn and chip. Heat it until it looses its magnetism and quench it in automatic transmission fluid diluted with a little solvent. Be careful because the smoke can flash fire, use long tongs and gloves. Then put the rough blank in the oven @ 350-400 for an hour. You can always experiment with scrap to find a hard AND flexible heat treatment. Forging with a torch isn't too hard either. The tool most used is a belt sander. It's easy and fun, pretty soon you get to reading a lot and buying flat stock on ebay.