View Full Version : Making a knife

2006-11-24, 04:54
Well Top started talking about getting a new knife, and then someone suggested he build one, and provided links. I looked. I saw the inexpensive options available in a kit knife and started getting itchy fingers.

Then I delved a little deeper and found fairly simple directions for building your own knife. All I needed was a good piece of steel to cut the knife out of, the ability to heat the blade in a fire, basic tools, oil, and an oven. I'm going to do it.

It's going to be a few days before I can really get at it (holidays, a funeral, relatives, 007, etc.) but I've gathered my materials and started some basic steps.

Got my saw blade, tools, and the template of the knife I plan to make.
Still need to find my propane torch, and have to decide what to make the scales (grips) of, but I can get along without the torch, and don't need to worry about the scales for quite awhile.

This is the 1st template of blade I plan to make.
The design is my own (I figured if I'm going to do it, why not go all the way).

A couple links to pages with many links:

SGT Rock
2006-11-24, 04:56
You can always do a wrap handel. A place to carry survival cord.

2006-11-25, 03:06
Was cleaning up my template and doing some measurements ...actually it's the drawing the template is going to be made from. Anyway, as I was adjusting blade and handle sizes I decided to make some adjustments to my original plan.

The blade is a little more traditional now, the finger hole moved some, and the thumb rest changed slightly. There might be more changes before I finish.
I'm planning to make a cardboard dummy and see roughly how it fits my hand (maybe tonight). There's only so much sizing you can do by staring at your hand. Want it right before I make the true template though.


Top, I thought about a cord wrap handle, but I don't think it would work well with the shape. I'm thinking I'll either use some wood that I have around, or I might see if I can get some scrap Corian from the local counter top people.

2006-11-26, 08:52
Well, I know all of you are on pins and needles :bebored: waiting for the next big update on my knife build.
Well here it is:
I made a cardboard mockup to try it for size, and ended up changing a few things. I made the finger hole larger and oval (for some reason oval works better) made the blade curve shallower, slightly altered a few curves, and moved the thumb rest out slightly.
-Don't know why, but when I upload my pics of the knife they've been coming out huge - have to go back and scale down the pics about 70 percent and upload again.

SGT Rock
2006-11-26, 09:21
It happens sometimes. I have gotten use to it and know what size to make my images these days.

Interesting knife design. I can't wait to see how it comes out.

2006-11-26, 12:41
What use do you plan for this knife? Doesn't look like a fish or game gutter 'cause the handle would be in the way when using it with the sharp edge up.
Looks a little like the (Old western?) "Sharp Finger".

2006-11-26, 16:38
DropKick - are you going to put some of those ridges on the thumb rest for traction?? I've forgotten the technical name for those ridges (and a whole lot more ), but they work really well.

2006-11-27, 03:01
What use do you plan for this knife? Doesn't look like a fish or game gutter 'cause the handle would be in the way when using it with the sharp edge up.
Looks a little like the (Old western?) "Sharp Finger".
It's more of a slicer (I was a cook). Though you can hold it upside down - I tried it with my cardboard copy - If needed you can also use the finger hole with your thumb.

The way I gut a fish, I don't hold the blade upside down anyway so that isn't a problem.

I thought about adding a gut hook to the back of the blade, but I've never used one and decided that I could get by without one.
-If I ever do try one I'll probably love it - am already thinking about making another knife with a guthook (after this one) - have done some preliminary sketches and have the metal.

I basically started this design trying for a knife that didn't need a guard and one you also wouldn't bark your knuckles when slicing on a surface.
- Plus I wanted it to be different.

DropKick - are you going to put some of those ridges on the thumb rest for traction?? I've forgotten the technical name for those ridges (and a whole lot more ), but they work really well.
Thinking about it. If I do I'm only going to do it into the knife metal and not the scales (handle). Have to wait and see, depends on how I feel when I reach that stage.

2006-12-20, 02:47
Getting really tired of not having time to work on this. Will be happy when the holidays end, and I don't have anymore funerals or other emergencies.

Finally just made some time - I went to the garage at 2 A.M.
Got most of the rough work done. I have the shape cut from the metal, edges smoothed, and almost have the first cutting edge finished.

I figure I'm about 1/4 to 1/3 of the way towards done.

Need to finish the first edge. Have been using a file, now I think I'll try using a mounted belt sander. Once I have it, I can rough out the final edge. Using either the file, or the sander, and finishing with my 3-way stone.

Then I get to temper the metal. And possibly soften it if I get it too brittle.

Then I make, and attach the handles, and I'm done.
no problem

SGT Rock
2006-12-20, 05:47
lets see some work in progress photos

2006-12-20, 11:15
What Top said: we want pictures!
What are you using for steel and how will you harden and temper your knife?
Inquiring minds and all that, you know.

2006-12-20, 13:00
I would suggest starting with a steel that is available, in the right thickness, and easy to work with. Once you are really happy with the form and function then use a better steel. Just a thought. You can make a pretty functional knife out of just about any steel.

2007-01-27, 00:24
Sorry I didn't get back to you sooner, this year just seems to be extraordinarily busy.

Haven't got real far since last time I posted on this subject. Just used the belt sander on it, did some smoothing, and finished the first edge. Plus I did a little work on the scales (handle). -I'm using oak as that's what I had lying around.

Now I need to get my 3-way stone out of storage (stored it away just a short time ago, as I needed shelf space - sometimes I'm not very bright). Finish the final edge and then I can harden it.

I plan to harden it by heating it in a fire until it loses it's magnetic properties and then quenching it in old engine oil.

If I need to temper it I'll bake it at 400F in the oven for 45 minutes and then let it cool (don't hurry the cooling). If it still needs it, I'll repeat the process.

I would like to provide pictures but the only camera I have (cheap digital) doesn't work except in full sunlight (and sometimes not then) and my scanner just died (why???) so I can't use it as a substitute.

Hopefully I'll get something decent to take pictures with before I finish.

2007-01-27, 22:31
What type of steel is it?

2007-01-27, 23:13
What type of steel is it?
I don't know.
I got it from my local hardware store.
It was a 4' x 4" x 3/8".
The Hardware people don't know what type steel it is either.
It was labeled weldable steel and I can tell it was cold rolled, but that's it.
I'm hoping it has enough carbon in it to harden well.
If it doesn't I've made a fine gardening tool and gained experience.

Been thinking I might carve a few throwing knifes out some of the leftover steel. As I don't need (or want) to harden throwing knives and it might be fun to play around with them.
-Maybe a tomahawk

2007-01-29, 10:13
It is probably a mild steel. 0.20% carbon is very common but it could be 0.30% or perhaps even 0.40% but less likely. Very difficult to get any hardness out of 0.20% from heat treatment. If it is only 0.20% you should just water quench it and not temper it, as it won't be too brittle, or that hard, even in the quenched state. You could try getting the edge harder by carburizing or case hardening it. Like I said though I think any steel is good for messing around with. That's what is so great about carbon steel. If you don't like it, just change it, but for a much harder steel to start with you could get a hold of an old leaf spring. You would definitely have to anneal that before working it, and temper it some after quenching it. With an oil quench you might not need to temper it though. Also salt water is a little less severe than fresh water, but more severe than transmission oil. For a low carbon sheet steel I might stick with the used motor oil, because you might get some carbon out of it. You never know. Another think you can do with a high carbon steel like a leaf spring is to pack some clay on it, exposing only the edge, and then quench it, and then remove the clay to temper it, or just quench it in oil and not bother with the tempering. I am lucky to have a Rockwell hardness tester here at work, and some small ovens. It make it easy. You should devise your own way of hardness testing, perhaps just a scratch test. I wouldn't be too concerned about hardness though until you think you have the exact shape you want. Even then, starting with a mild steel and finding a way to make it strong and hard can be very rewarding, and you would be retracing old footsteps. Traditional weapon bronze might also be very interesting to work with. It was harder and tougher than most steel in its day, and iron weapons only initially took over because they were cheaper for mass production. Hardness and toughness came later, and the methods were lost and rediscovered several times over, so have as much fun as possible along the way.

This is a good reference for working with plain carbon steels:

This you might find particularly interesting:

Carburizing: A process used to case harden steel with a carbon content between 0.1 and 0.3 wt% C. In this process steel is introduced to a carbon rich environment and elevated temperatures for a certain amount of time. Because this is a diffusion controlled process, the longer the steel is held in this environment greater the carbon penetration will be and the higher the carbon content in these areas. The part is then quenched so that the carbon is locked in the structure. The hardness is moderately increased, but it can be hardened again through flame or induction hardening. It's possible to carburize only a portion of the part by covering it in copper plating or coating it with a commercial paste. The following are some examples of carburizing processes:

Pack carburizing: Packing low carbon steel parts with a carbonaceous material and heating for some time diffuses carbon into the outer layers. A heating period of a few hours might form a high-carbon layer about one millimeter thick.

Liquid carburizing: This method involves heating the part in a bath of molten barium cyanide or sodium cyanide. The surface absorbs both sodium and carbon this way.

Gas carburization: Parts placed into a furnace at 927 C (1700 F) containing a partial methane or carbon monoxide atmosphere. The parts are then quenched.

Carburization may also be accomplished with an acetylene torch set with a fuel rich flame and heating and quenching repeatedly in a carbon rich fluid (oil).

2007-07-10, 03:21
Well after starting this knife and then letting it sit on a shelf in the garage for months I'm finally back to working on it.

Built the handle for it this evening, still needs a little bit of hand sanding before I oil it, but basically it's done.
I decided to go with a handle on only one side of the blade, as the oak I used will be thicker and stronger this way. Besides it was easier to do and I actually think it will work better this way. - Does make it more of a right handed knife though.

Wish I could post a picture but I can't find my crappy digital camera, and my scanner died.

Tomorrow I'm going to try tempering the blade. I really hope this steel will take a temper. If it doesn't I'm going to have a funny looking garden implement.

Either way I'll try to find my digital and take a picture of it tomorrow.

2007-07-10, 03:23
Oops- just remembered can't work on it tomorrow (have to go to a pot luck) I'll do it the next day.

2007-07-10, 06:41
Found my piece of garbage camera, thought I'd take a picture so you could see what I've done so far.
The pictures are very poor quality and the only place I could find with enough light for the camera to work was on top of my sink in the bathroom. This is also why the item added for scale is a tube of toothpaste .



I'm hoping I can get better pictures after I finish making the knife.

2007-07-10, 10:05
Looks cool, that offset handle should make it a good skinner. It would be a useful kitchen knife also, very handy.

2007-07-10, 13:41
I like it DK. Very neat. Let us know how you treated the steel.

2007-07-11, 00:37
Came back from the pot luck and thought I'd finish sanding the handle tonight.

Now comes my important knife making safety warning:
If you are working on a knife handle while it is attached to the blade: tape the edge of the blade!

Sliced myself good. Added to my scar collection and bled like a stuck pig all the way to the bathroom. I feel dumber than a box of rocks. It was just plain carelessness.

Only got one finger, but it was my right index diagonally across the first joint and clear down to the bone. Awkward place to be wounded.

I did finished my sanding. Had to change bandages a few times but it's stopped bleeding and is fine now. Typing is a little difficult though.

Oh well, a week or so and I'll be good as new.

2007-07-11, 01:04
Well like they say [ Man play with fire get burnt ] or [ Man play with knife get cut ]

2007-07-11, 21:55
Perfect wound place for super glue. And yes, it's safe. They inject the same, identical chemical into people's brains to seal minor bleeds. It'll heal faster as the wound wont be getting pulled apart at all. Just clean it real well before hand.

2007-07-12, 07:26
Dang it! had this whole message just about typed out and the server reset and wiped out all my work.


Tempered my knife tonight and I'm very happy with how it went. Don't have any way to test the hardness, but the blade seems hard and not brittle.
Tested it with a file (suggested test by knife makers) and the file slid across and didn't grab. Also did some sanding on the blade to clean it up and the steel is definitely much harder, but as I said before it doesn't appear to be brittle.

How I tempered it:

My forge was a small round bar-be-que.
My fuel charcoal briquettes.
I used a small clip on fan to keep the fire hot.
I quenched it in old engine oil.

I started the briquettes burning in a coffee can with the top and bottom cut off and holes punched in the sides. At first I tried to heat the blade in this coffee can, but I couldn't get an even enough heat on the entire blade, so I dumped it out.

I put the blade amongst the briquettes, piling them around and over the blade. I had the fan blowing directly on the briquettes.

After about ten minutes I pulled the blade out and tested it with a magnet. The blade was glowing red hot over it's whole surface and had lost its' magnetic properties. I quenched it in the oil.

I had a lid in case the oil caught on fire, but it didn't. After a little while I fished out the blade, wiped it off, and tested it with a file to see if it had hardened.

It was still covered with a "baked on" covering of the oil (like tempering in a cast pan). I sanded this off the blade, making it shiny, but left it on the metal of the handle (I'm going to cut food with this knife - didn't feel old engine oil was a good mix).

I reattached the wood handle, which had been soaking in olive oil all night, and while at it coated blade with olive oil.

I still want to get my 3-way stone and give it a final edge, but other than that and making a sheath, I'm done.:biggrin:

I'll try to get some pictures of it in the daylight tomorrow.
(with my crappy camera - wish my scanner still worked - it took much better pics)

2007-07-18, 12:16

Incredible website for knife builders!

2007-07-18, 22:30

Really great discription of your heat treating process. I am lucky because I have a harness tester and a couple of small funaces in the lab in the room next door here, but I still like more primitive methods. Sounds like you've got a great knife. Medium Carbon Steel perhaps, like 1040, maybe higher. A very mild steel would not harden much even with a water quench. You would never know for sure because it might not be plain carbon steel, but if it was a plain carbon steel you could find out how much carbon it has by doing the same thing and doing a water quench and then measuring the hardness with a hardness tester. I am lucky because we have one here. Then once you knew better what it was, you could decide what heat treatment would be best. Perhaps a water quench followed by tempering. Perhaps an oil quench. If it is on the low side of a medium carbon steel then it might not be too brittle with just a water quench. Anyhow, you would probably end up doing exactly what you did, austenizing followed by an oil quench. Transmission oil is a little safer than motor oil, and pretty much exactly what is used for oil quenching, but motor oil is safe enough. Whatever works.

Of course as you know there are some other interesting things going on. By leaving it in charcoal, perhaps with a coat of oil, you can get some surface hardening with the carbon diffusing into the metal. The other thing to play around with is to cover the back of the blade with clay exposing just the edge for the charcoal treatment and the quench also. The objective is to get a hard edge, but a tough blade. This wouldn't help if its a medium carbon steel, unless you get a lot of carbon to diffuse in. I would be more useful for a high carbon steel. Anyhow, have fun. In my opinion working with commonly available plain carbon steel is more fun than just going out and getting the perfect steel for the job, if there is such a thing. It's even more fun if you don't know exactly what steel it is, at least to start with.

Anyhow, I should stop my yapping and build myself something for a change. Cheers. :beer: