Hardening and Tempering a Bush Knife

[dirtbikemechanic]

I'm making a machete like the one in The Book of Eli. So it's 1/4in. thick, would i use basically the same method to temper it?

[Ghostkamo]

@dirtbikemechanic I don't do knives that large but, the same method should work. Be sure to wear protective clothing.

[porygon110]

@dirtbikemechanic i know nothing of steel and heat yet, but i think you would best off look into how they temper a kukri, its a think choper of a blade.

[nickolusthegreek]

@dirtbikemechanic That "machete" is called a "Kukri" I believe... It is traditionally used by the Gurkhas in Nepal where they similarly forge these blades from the rear leaf springs of trucks because of the steels strength.

[PK102260]

Awesome vid. Is that a special steel or will mild steel work?

[Ghostkamo]

@PK102260 That is hard steel that I softened before aI formed the knife. You can use annealed steel.

[janken919]

Do you have to quench in warm oil, or can it be water?

[Ben762x51]

Nice Video. I was wondering if you could answer a question for me? I'm also working on a bush knife right now (first one), It's .40" thick, and i'm not sure what kind of steel. I bought the steel almost 15 years ago. That being said, could you (or anyone else) tell me approximately how long it might take to get it up to proper temp for hardening?

[Ghostkamo]

@Ben762x51 It will only take a few minutes for hot coals to reach temperature if some air is forced on it. You will first see gasification, that is when the gas coming off the coals begins to burn. Then the coals will turn a white/orange color. Does not take long. When the metal is no longer magnetic is one way people know the temp. is right, some do it by sight. I'm not claiming to be an expert at this, I do it for a hobbie and learn more as I go. Please remember to be safe.

[Ben762x51]

@Ghostkamo

Ok cool. Thanks for the reply. I was also wondering do you need to use actual coal, or can you just use charcoal briquettes that you would use for grilling food? Sorry if it's a stupid question. lol My first time. Nice job on the knife by the way.

[Ben762x51]

@Ghostkamo

Thanks for the reply. I did a test run on a piece of steel that is about th same thickness as the knife i'm making, but was unsuccessful at getting it hot enough. The steel was almost 1/4" thick though. I was using homemade charcoal, and ended up running out of it. Are you using charcoal, or just coal in this video? Any idea where I could pick up some coal? I assume it would burn longer/hotter no? Thanks again, great video.

[Ghostkamo]

@Ben762x51 I get my coal from sifting ashes after a fire.

[Ramble96]

is there a reason why you don't harden the handle part of the knife ??

[5Metalgod5]

@Ramble96 there is no need to harden the tang, you should only harden the blade so it keeps its edge.

[Ramble96]

@5Metalgod5 thanks a lot for the information bro ; )

[roberto25721]

why did you bake the knife in the owen? ( my spelling sucks ) and could i use motor oil? or does it need to be some special type of oil?

[Ghostkamo]

@roberto25721 Use any medium grade oil you can get. I Tempered the knife in the oven in order to toughen the metal, in other words, this makes it less brittle and more pliable without giving up strength.

[Avatar230594]

You have an oil fire. Does that just go out by itself?

[Ghostkamo]

@Avatar230594 No, oil fires are dangerous and must be smothered by blocking the oxygen with anything stable like salt, dirt or a metal lid. NEVER use water on an oil fire.

[Survivalvideos1]

hey this is a pretty ingenious forge setup. with my forge i do blacksmithing and quenching. Basicly mine is a hole in the ground with bricks for insulation then i have a hair dryer flowing in air like yours. This would be a great portable forge you could just keep in the back of a truck or something. Nice video keep up the good work

[7x57mmMauser]

Some steels like "W" series tool steels from old files etc. need water and not oil.

[5Metalgod5]

@7x57mmMauser if i where to make a knife out of spring steel would i use Oil or water for the quench?

[7x57mmMauser]

@5Metalgod5 each metal is different so I couldn't say off hand. Usually old spring steels are 5160 and they are oil quench though some newer spring steels are air hardened or water hardened. It really depends on the exact metal type and the mfg's recommendations.

[LockDOTspot]

make me one :o

[TeamInferno81]

How well does the knife keep its edge?

[AdamNinjaXXX]

would it work if the steal i was useing was stainless steel?

[Zacistan]

is the temperature in degrees celsius or farenheight?

[Ghostkamo]

@Zacistan F not C

[DackIsBack]

What are the Essential tools and material I would need to make a similar blade?

[48vdcwrld]

I've used Veg oil, it seems to work fine....

[ernstbecker1]

Try peanut oil -- it works.

[JMEBF]

Man a little help. I'm from Chile and I'll soon be travelling to Patagonia. Because I'm a jack of all trades I want to make a pair of crampons out of a 50 liters stainless steel keg. Do you think that hardening technique could work? I mean for the spikes, the tips, or they may beome hard but breakable? Thank, and congrats for your useful videoclip. JM

[svar1shot]

what did you use for a fuel sorce wood or coal or what?

[Ghostkamo]

@svar1shot I sifted coals from a wood fire. I have a wood stove and save the coals after the fire goes out. You can do the same with a camp fire.

[dimahockey]

do you have to use used oil or new

and why

[Ghostkamo]

@dimahockey new or used doesn't matter. I used old oil that came out of my truck.

[yapxw9]

can veg oil be use

[Ghostkamo]

@yapxw9 I've never tried it, good question.

[jjaayypp963]

@yapxw9 I have heard that veg oil can be used, and it works good. I have not tried it, but I will soon.

[cupcakecooper]

Is it absolutely necessary to harden the steel before usage, and if so why the oil?

[Ghostkamo]

@cupcakecooper If you do not harden the steel will not hold an edge and can even bend. The oil draws the heat from the blade quickly without cracking the steel. Quick reduction of heat hardens the blade.

[scrapthrall]

Is that 350 C or F?

[Ghostkamo]

@scrapthrall F not C

[scrapthrall]

@Ghostkamo

Thanks,that was the only thing I wasn't sure about.

The rest of the vid was brilliantly clear.

(My first two blanks are now waiting for some old pans...:) )

[HomeMadeGunNut]

Lmao Ghost It Looked Like Your Coat Was Gonna Set On Fire At 1:35! Great Vid, I Hope My 1st Knife Turns Out As Well As Yours.

[blacksmither1]

very good sir very good

[roglet123]

really great vid, thanks

[versatilechicken]

can you reuse the oil?

[Ghostkamo]

@versatilechicken yes, I used the same oil several times.

[hunterdka]

why is it better to use oil instead of ice water?

[fatboy30179]

@hunterdka Casue Steel gets its strength from the oil inside of the metal. When you heat it the oil is removed by adding it back in you get the strength back. There is more to it but that is just a crude explanation. I have heard WD-40 works better casue it is thinner and penetrates better. But I havent made a knife or anything close. This is just stuff I have read.

[ratbertovich]

@fatboy30179 you cannot take anything out (well actually you can cause some carbon to escape, degenerating the steel) or put anything in the steel outside a steelworks. Its contents change crystalline structure with temperature, so you can anneal it (soften it for working), work on it, harden it and temper it (soften very slightly, enough for it to flex). WD-40 as a hardening coolant is a very bad idea, as it cannot cope with temperatures that high; you'd probably have flames a few yards high.

[ratbertovich]

@hunterdka the trick is in cooling the steel quickly *and homogenously*, i.e., keeping the temperature differences along the blade in a very narrow range, so that you have the same amount of martensite (very hard form of crystalline structure that determines the steel's hardness) forming at any point on the edge. While water is a good, traditional coolant, it does not afford homogenous cooling as good as oil.

[nedge46]

my first question, is the knife stainles, if not?? Two, how did you prevent the blade from rusting???

[Ghostkamo]

@nedge46 This is non-stainless. I made it from an old file. Most of my knives are stainless steel but, I do have some non-stainless. I keep them protected from rust by cleaning and waxing them after using (or use a light oil). Also, I recommend storing them outside of the sheath if they will be sitting for a while.

[nedge46]

@Ghostkamo thanks. i knew that non-stainless blades were made but didnt know how people prevented rust

[CoolKillerClan]

i here every one talk about the forge like if it a siense it a art

[Ghostkamo]

@CoolKillerClan Excellent input, I have to agree with you. For me, this is more about personal expression and exploration rather than hard science. Unfortunately, even I get caught up in the details at times. thanks for the input.

[CodyOebel]

@CoolKillerClan

IT'S ALLLLL ABOUT TEMPERING PAL :) An art of it's own. I dont use power tools for the knifes I make. I also will not give someone a knife I made if it wont hack a 2x4 in half 3 times and still shave. For example.. I just made a big texas bowie by heat and hammer no power tools. Check out my channel, and click on finalvideo to see it from start to finish. I burned that video on a DVD for authenticity to go with the knife.

Ghost here knows his tempering :) Non-Magnetic :)

[CodyOebel]

OOOps.. mistake. Ghost you temper using an oven ? BAD BAD BAD :)

Nahh some people like to temper with an oven. I temper with spine in coals. Watch the steel turn blue-bronze-straw. Depending on the knife steel getting the edge a particular color comes down to knowing that steel. For 5160 I let blue the spine, light straw the edge on first temper, air cool, second temper I light bronze the edge, air cool, third temper bronze the edge. Good n tempered.

Continued

[CodyOebel]

The "ONE AND ONLY" thing I dont like about tempering in an oven.

Is first off the entire blade gets tempered. Depending on the steel. Put it in a vide and try to flex it, and it breaks, or bends and doesnt return to position. This is why I spring quench the blade, hand temper on coals, and you got flex, and edge holding, but it takes a little longer. I'm in texas.. so obviousy ghost here would have to freeze outside to do the same old school temper method LOL

[RainMan002]

@CoolKillerClan What's the difference? Good science is beautiful.

[musk8teer]

I'm a beginner. What type of oil is that ? (Motor, cooking, some special type?)

Also, when making a knife from scrap metal, after the shaping, grinding sanding etc, is it necessary to heat and quench in oil. Would water cool it too fast? How long do you leave it in the quench solution? How many times do you heat and cool? Thank you.

[knifemanconnor10]

great seriesof vids, thank.

[versatilechicken]

is doing this neccessary or isit just to strengthen the knife?

[Ghostkamo]

@versatilechicken If you do not harden and temper the knife it will not keep it's edge well and will be more likely to rcieve damage like dents, scrapes and bends.

[versatilechicken]

@Ghostkamo oo thanks for that im new to knife making and stuff so i'll probrably have to build a forge =)

[Vot63]

Cool vid, very helpful. Thanks!

[pyrea17]

that's great- not at all a bad knife

[john1112112]

do u sell ur knives? if so, do u go to shows or do u have a website r store?

i love how the blade ignites the oil. how do u put the fire out?

[Ghostkamo]

@john1112112 Sorry, I don't sell the knives. I make them for my wilderness and survival treks. I put the fire out by placing a metal lid over it.

[john1112112]

@Ghostkamo very cool, i really wanna get into making knives, but i need more knowledge about tempering and heat treating, as well as equipment, the blow dryer is a great idea. i'm not sure how i forgot that fire needs oxygen, lol whatever =]

[omgsayavailable]

Thank you very much for these vids! Btw, would using clean oil have any adverse effects on the blade? And how long did you temper it for?

Thanks you again for the series

[Ghostkamo]

@omgsayavailable Clean oil will work. I believe I tempored this one for nearly an hour.

[MrSupnoobs]

man that was very smart to use the hair dryer i would have blown with my mouth or something lol

[snuffying]

why does the oil need to be warmed? and is it okay if i use UNUSED oil?

[ImmaculateSludge]

@snuffying the oil is heated to that it will cool the steel more slowly to allow for higher ductility. you can use clean oil if you want... its just a good use for old motor oil though

[snuffying]

@ImmaculateSludge ok thanx for the reply man!

[darktim99]

MANY, MANY thanks. ive alwasy wanted to know how to do this. its SO simple too.

[MrCelloman21]

how do you sharpen a knife?

[crackwiser]

After heating the steel above 727 (centigrad) here the steel has an austenitic structure, you quench it with water or oil to room temperature. This changes the microstructure to martensite. Martensitic structure is the hardest of steel microstructures which you can achieve, but sadly it is too brittle to be used effectively. Therefore after quenching, you have to temper it between 250-650 Centigrad something for an hour or two.This makes the steel gain some ductility.

[crackwiser]

After heating the steel above 727 (centigrad) here the steel has an austenitic structure, you quench it with water or oil to room temperature. This changes the microstructure to martensite. Martensitic structure is the hardest of steel microstructures which you can achieve, but sadly it is too brittle to be used effectively. Therefore after quenching, you have to temper it between 250-650 Centigrad something for an hour or two.This makes the steel gain some ductility.

[fcpoker]

Hi there Ghostkamo i like u channel alot and specially these 'knife making vids'. U got me at the point where i want to make a knife but i just can figure 1 thing out : do i need to do the hardening first or the tempering? I mean if i got my metal piece i saw it in shape first? harden it fist then temper it scharpen it? or even an other order? On youtube everyone does it different, what you do?

Thx alot for the help.

[Ghostkamo]

First, the metal should be softened in a camp fire and left to cool if it is too hard to cut, file and drill.

Second, shape the knife.

Third, harden the knife with the forge and dip.

Last, temper the knife with sustained heat of about 300F.

I hope this helps

[fcpoker]

Sure thx verry mutch !

I wil get started and make video to show how i did :p

grtz and gl

[monstaquest]

I really enjoy your vids where you make stuff. You have got me eyeing my wife's old cookware, and my old files after this one.

[Ghostkamo]

Thanks, there's real satisfaction in doing this at least once.

I was glad to agree that the wife needed some new stuff. LOL

[TheSpunFire]

I've been looking for videos like this for ages. You're totally subscribed to my friend.

[Ghostkamo]

Thanks, I try to do a couple knives each winter and test out a slightly different method each time.

[Ghostkamo]

Hmmm, I get a lot of different opinions on that. I can tell you that I've seen videos of a guy cracking his blades in half using water. The proffesionals seem to use oil a lot.

So far it's worked for me.

[sjeter61]

Thanks,  I have a old file Im gonna start on this wknd.

You have a good channel & some real informative vids. glad I found it.

[Ghostkamo]

Cool, if you can, post some of the work in progress.

[sjeter61]

Very nice , I want to try this. Forgive my ignorance,,, but why do you warm up the oil, I  dont know

Steve

[Ghostkamo]

Several sources that I have checked with suggest that warm oil reduces the risk of cracking the steel as opposed to cold oil or water.

[bushcraftbartons]

Job very well done Kamo.. 5/5

Mike

[nj4x4fever2]

You did a fantastic job on making that blade! I think it would make a perfect gift for one of your fishing buddies, like me!!

5/5

[Ghostkamo]

Thanks, I am thinking about making some that I'll part with. I'm still in the learning process with finding out what works best so, the quality of the knives should improve soon.

[medicjimr]

Awesome this exceeds 5 stars so 10/10 this was is a great series to watch thanks for sharing my friend.

[Ghostkamo]

Thanks, I posted a lot of details on what I did. I hope this encourages others to try a little project of some sort. There is a lot of satifaction in making something for a hobbie.

[davidnightingale]

5 stars. Awesome, great job. Cheers

[aokspage]

so awesome. I am sure the final will be great

[bassfuryvi]

effective little forge you have there..once you lower the blade in the oil,, I would gently move it back and forth a bit to encourage cooler oil from the edges of the can to get to the blade to promote a more even hardening but it was a small knife and a big ole can of oil so it's probably more than fine,,gotta commend you on the profiling with the squared off guard area,,that looks like a lot of patient work in that knife..looking forwards to the handle vid..5* kamo!

[Ghostkamo]

Thanks, you're the second one to suggest moving the blade in the oil. I'll give it a try on the next knife. On the next knife I will not post details but will describe what process I did and show results.

[capreolus4]

awesome.a wood handle and wooden sheath would be great.

[Ghostkamo]

I think I will go with the wood handle but, I'm still wondering what to do for a sheath.

[mem7048]

A 5 dollar purchase at a flea market for a toaster oven will stop youir old ladt from freaking out on you!

[Ghostkamo]

Good tip. Yea, you might want to wait for the lady to go shopping before you stick a big knife in the oven.

[187plumber]

great video knife looks good

[pk066392]

looks good kamo, im going to make another knife soon, mayb i will document it on video this time

[Ghostkamo]

Thanks, I'm looking forward to seeing your work.

[beast12101]

looks great, what did you decide for the overall blade length?

[Ghostkamo]

The "cutting edge" blade length is 5 and 5/8 inches in long. The blade after handle is 5 and 6/8 inches long. The handle is a total of 5 and 1/4 inches, with the wood part being 4 and 1/8 inches.

This is a very non-typical knife that adresses simplicity, survival and covering some basic needs quickly by using minimal skills and tools. I will move on to more refined knives in the future.

Thanks my friend for your input,

Kamo

[Ghostkamo]

Thanks, I plan to continue trying different methods and becoming more refined as I move forward.

[MrCableguyken]

move the blade around some in the oil and it will cool it more evenly....Great job on a first knife Brother.

[Ghostkamo]

Hmm . . I don't know for sure but, I heard that the blade should be dipped straight in and held motionless for a minute.

BTW - I time lapsed that part.

We'll have to investigate this a little more, I have been starting very basic and trying different methods each time.

[MrCableguyken]

Yeah, I get all kinds of different stories too when I started making knives...Look and see if you can find wayne goddards $50 knife shop...lots of great info in there...I know where to get it, just dont like to read...lol If you want it and cant find it let me know, and I can get it for ya and send it your way

[19ADC67]

awesome project Kamo!

[Ghostkamo]

Thanks