Creating a bush knife with layered wood handle

Step 3 Metal work

Now you have a knife shaped piece of shiney metal, it's time to give it a edge. Not sharp, but taking off the square edge while it's still unpolished.

I used an angle grinder for this step, very carefully and lightly brushing over the edge until it was at the right kind of angle. Then turning it over and doing the same on the other side.

The masking tape was intended to act as a visual guide, but didn't really help much.

Do this until you are happy with the shape and blade angles, then temper the metal with the method of your choice.

I opted for the quick and dirty method of heating and quenching a few times. With no forge to hand, I used a blowtorch to heat the metal before dropping it into a bucket of water. My intention was to focus the heat on cutting edge of the knife, there seems little point in making the whole knife harder and more brittle. Some flexibility will add to the durability and strength.

Comments

[weloveclover]

Having made a few knives myself I highly recommend that you DO NOT use an angle grinder to put in the edge as it leaves dents which take for ever to file out.

[punkhead58]

I agree. Trying to do precision work with an angle grinder is like a bull in a china shop. Although you can get relatively accurate results with a bench grinder, I recommend taking the time to use the good ol'e steel file.

[diocite]

A nice looking knife. What type of steel was the blade made from? It may not hold an edge as well as you would like because certain steels are not as heat treatable as others. I usually use O1 tool steel which is readily available and relatively cheap. Leaf springs from truck also work if you specifically wanted to make it from scrap. Also unless you heated the entire blade red hot all at the same time then your quench will not leave the blade evenly treated. I have had success with a charcoal chimney and natural wood charcoal (not briquetts). Bring everything to red hot, drop the blade into oil or HOT water, sand it till shiny, then heat slowly over the charcoal till the edge of the blade is yellow. Or alternately heat the blade from the back edge with a torch. -Diocite

[nunvikingsofthesea]

would a wood saw blade work?

[diocite]

Old hand saws were made from medium carbon steel. Somewhere in the range of .8%-1% with little in the way of alloying elements. O1 is .85%-.1% with a bit of manganese. Should work, but I think a saw blade would be too thin to make a knife of any significant length.

[nunvikingsofthesea]

well, wat do u think is a something good that i can convert into a bush knife, because there is no way i can find the steel, so i can't build it from scratch.

[Boy Scout]

You could use an old hacksaw blade.

[diocite]

Files, lawn mower blades, circular-saw blades, car leaf springs, garage door springs, springs of any kind, axles. Any steel that is temperable. Try flea markets and scrap yards. Yard sales even. You can test for temperability if you have a bench grinder. High carbon steel will throw a shower of really bright white sparks. Low carbon steel won't throw very many sparks and they should not be as bright. Compare the sparks of whatever you think might be high carbon to the sparks thrown by a common nail. - The preceeding paragraph was a rough summary of Chapter 2 of "The Complete Modern Blacksmith" by ALexander G. Weygers. I have not used this method and cannot promise that it will work for you. Also if you bring a section of steel up to red hot then quench it, if it is high carbon steel, it will get real hard. Take a file to it and if the file skates across the surface of the metal then it is temperable. This is a method I have had success with.

[nunvikingsofthesea]

Where could u get O1 tool steel?

[diocite]

McMaster-Carr is where I get mine. A2 also holds a good edge.

[milamber]

u can buy knife steal called 1095 from steal reatailers it holds an edge of up to RC 58 and is easy to heat treat to that point

[diocite]

Another heat treatable carbon steel. Primarily used for springs.

Hardness comparisons for various steels are here:
http://www.mcmaster.com/param/html/steel/default.htm

1095 is toward the center, left. A2 and O1 are way right (harder) and will hold a better edge.

[atombomb1945]

When talking about a Charcoal Chimney, would that be the chimnerias that people have in their back yards, or the ones that are used to start a gril?

[diocite]

I just use one that I would use to start the grill. I also use these to start my coal/charcoal forge (made from a large tractor brake drum). It makes starting the forge very quick.

[uncle_fester]

Diocite, if you havent already, it would be great to see a work up on your forge.

[diocite]

I am away from home for a while due to work. I will see what I can do when I get home.

[chunkymuggen]

i made a thing out of a charcoal chimney that heats the coals really hot; hot enough to reach about 1000 degrees. use an old charcoal chimney, and attach a heat resistant metal hose to the base. attach an air mattress filler-upper to the other end of the hose. the air keeps oxygen going to all parts of the coals, making them super hot. also, you could (if you know how) attach some kind of airflow regulator; either an electric one attached directly to the blower, or (easier) attach a hose flow nozzle to the pipe. either way would work. :)

[diocite]

I don't even bother with a blower, though I do have one on my forge. I just light up the chimney and let the charcoal catch.

[chunkymuggen]

well, it'll be a lot hotter with a blower, but the coals will run out faster. also, i think there are coals you can buy that burn extra hot.

[biolethal]

those coals that burn extra hot are A:toxic to the environment because they have a bunch of chemicals in them.(but then again burning charcoal isnt eco-freindly either) B:they are allot more spensive... biolethal

[icanryme2002]

wood is carbon neutral

[chunkymuggen]

yeah, but you can get a bunch for expensive. anyway, if you would rather buy a real forge for a couple hundred, thats alright. unless you're poor, i dont think the slightly raised price should be much of a blow to your wallet. anyhow, i would rather get my steel really hot and get it evenly heated so it gets maximum strength. about the environment thing, I'm not a tree-burning, paper-wasting, littering, plastic-burning, earth hater; i just think earth is fine. i will probably be dead before the enviornment changes too much, but i dont thing burning some chemically-enhanced coal will cause the earth to explode. no offense by the way.

[atombomb1945]

Ok, I will bite. Where do you get a "Real Forge" for only a couple hundred?

[chunkymuggen]

One word:
EEEEEBAYYYYY

[biolethal]

A couple hundred?????!!!!!!! wow. wow... i have about 21$ in my wallet, and $0 in the bank. that would sorta be a blow to the wallet. acually, a fatal one. hehe... you probably have around 200$ a year to spend on diy. I have about 70. -Biolethal

[chunkymuggen]

ok, that sucks

[diocite]

I use charcoal from these guys:

http://www.cowboycharcoal.com/

Real hardwood charcoal, like they deforested Europe to make back in the day. It is cheaper by the pound than Antracite or bituminous coal here in Cambridge, MA so that is what I go with. Also I can buy it from the grocery up the street at a discount when I buy in bulk.

Regular charcoal briquettes are not suitable for any hot metal work because of the additives in the coal.

[42ndOddity]

So far as I can tell, it's just mild steel. In all honesty I like making the handle more then the blade, so it was a little neglected. If (When) I do this again though I will certainly take that into account. I have lots of tool steel handy, but all in small pieces unfortunatly, blanks for lathe tools. A trip to the local scrapyard may be in order...Also I'm intrigued by the case hardening process, heating the blade and smothering it in carbon powder. If I manage to do that then I may publish an instructable to extend this one. Thanks for the advice.

[Tracy]

Try lawn mower blades. I think they are something like 1055. Tough, easy to resharpen; good for a rough-use knife.

[Boy Scout]

Used lawn mower blades work very well as they are already in a rough blade shape. Plus they cost next to nothing. You can usually get a maximum of 2 knives from a lawn mower blade.

[tigerdog330]

the only downside to that is that theres a hole in your blade then.... i made mine out of a edger blade.. i didnt even need to harden it

[dj_nme]

If you have access to a furnace which can reach 1100C, then you can case-harden using carbon/charcoal granules and an air-tight heavy-gauge metal (steel or stainless, NOT aluminium) box. The alternative is to flame harden the surface of the steel using an oxy/acetylene heating torch set to a carburising flame. LPG or natural gas is not an option, because it is always an oxidising flame which will ruin the surface rather than adding carbon to it. Whatever way you decide to try, it is a very good idea to have an experienced tradesman (boilermaker or blacksmith) on hand to either help or do it for you.

[biolethal]

i think that if you have a blacksmith on hand, it wouldent really be
Do
It
Yourself
but thats just my opinion

Biolethal

[dj_nme]

"on hand" doesn't have to mean "right beside you guiding your hand" or "doing it while you watch", in this context I mean "that can easily be contacted to find out the straight dope". Having some-one who is skilled in what you want to do available so that you can pick their brains for info is a very good idea.

[diocite]

I don't think you would get even a very thin layer of case hardened steel without heating the object for a very long time using a torch. Have you had much success using this method?

[thoraxe]

case hardening is a complicated and painstaking process. it requires the steel to be kept at yellow hot for hours on end in a sealed iron or stone box with a charcoal packing surrounding the steel. The goal is that hopefully some of the carbon from the charcoal will find its way into the outer surface of the very hot steel, but it would only be hardened to maybe 1/32 of an inch, depending on the time spent and heat achieved.

[dj_nme]

I have used this method to make a cold-chisel from a mild-steel bar. So, yes it does work. Just not very quick, only 5 to 10 minutes. But this can seem like an eternity when all you want is the finished product. Furnace case-hardening is an "overnight" process, so it is glacial by comparison and so not really for the impatient.