DIY Tempered Carbon Steel Picks (great for any hand tool)

[snelprobe1313]

when tempering the best liquid to use, if your makeing your picks out of some kind of steel , when you heat them up to what ever temp quinch them in used motor oil, the oil will ignite so be careful but all of the excess carbon in the oil is absorbed into the metal resulting in a DIY tempered carbon steel pick.


I've done it to all of my hamers and chisells, for that matter almost all of my hand tools and i get alot more use out of them

1. Metal pan to hold the oil while your quinching

2. Used motor oil (the thicker the better i.e. the oil out of your car after going 10,000 miles without an oil change for best results)

3. A good source of heat, and it would be wise to do this out side because the hot metal will ignite the oil and produce alot of smoke

message me back or post a reply for more info or pics

[zeke79]

A fire extinguisher
Safety glasses
Welding gloves

The list of required things for this method is pretty long. Not really something I want a 15 year old newbie attempting in daddy's garage!

[Krypos]

yeah, my suggestion here, would be that if you're going to post about a method to quench your steel in motor oil, that you go through the full safety/procedure here.

there are a lot more young people here than one might think. some as young as 14 or so.

[UWSDWF]

nothing says lovin like a flamming bucket of motor oil

[raimundo]

not sure the carbon would acually alloy at that temp, but since picks are small, they carry little heat, once submerged in a large body of oil that heat is quickly gone, and the only real danger of fire is when the hot pick hits the surface of the oil, at the surface there is the third element, oxygen, under the surface you have only fuel and kindling temp. Oil does not easily catch fire, though when lit its not easy to put out. if you use a very small amount of oil, where the pick does not submerge then the heat will not quickly dissapate and the oil will light. The whole thing about oil lighting up is really about how much heat a particular mass of metal can carry, if the guy is heating a hammer head, this will be capable of carrying far more btu's than a pick so its in a different ball park, shape is also important, if its thin like a pick, it has a lot of surface to dissapate heat quickly, while a hammer head is capable of keeping heat much longer
if you use a sardine tin under the stove fan and keep another can near to cover the fire if one starts, that should control easily unless the operator is a complete putz.
I have also wrapped picks in tissue and poured 3in1 oil into the tissue, then lit it. this leaves some interesting random colors in the metal, I have seen violet, and sometimes even something as rare as green, but these colors do not go deep into the metal, and quickly rub off from fingers, still for a while, its something to see.
As the more careful posters above said though, probably best to do it outdoors. After a certain age, common sense is assumed as is personal responsibility, while it will take a lot longer for someone to develope planning and expertize.

[Schuyler]

I may have to try that coloring method, rai, very cool idea. And great info too.

[Wolfe]

FIRST.
Why on earth would you temper your hammer/chisels. you only make them less efective at thier job. all your doing in tempering is making the metal more malleable.use your head nails are hardened.And chisels are hardedned for a reason also. The people that made that hammer and chisel know a hell of a lot more about metal than you. They made those objects with spicific metals and heat treated them in spicific ways to get the toughness/strength to hold up against tons of abuse.

SECOND
You only use oil or any liquid to cool metal when you do not care if retaines internal stesses ,distortion,and fractures. And let me tell you buddy i care if my hammer/"othertools" have iternal stresses or fractures.

THIRD
To cabrorize steel you have to heat the steal to a temp. of 1500-1700 degrees. And if you think for one second that sticking that into some old motor oil isn't going to cause instant flash you not that bright.

FORTH
When you carborize steel it make the steel brittle.When you pick a steel for pick you not looking for a harden steel more of a strong steel in one that is able to bend and flex as needed and is also shock resitant.Not a steel that will snap off in the lock when you apply pressure

Let me give you a tip buddy dont post misinformation,Especialy misinformation that will end up hurting somone. Aslo use your head before you go spouting anything else.

[raimundo]

to whom did you address that final comment? theres been a number of posters here. you are right about carborizing steel at high temp. and of course that temp will cause oil to flame if the light pick does not sink below the oxygen level. but the fact is that you can put a lot of BTU"s in a thick chunk of metal like a hammer head and it will cause problems instantly at the surface, and if it dosent sink beneath, it will certainly cause fire. but a thin easily heat sinked piece of metal would have a lot of trouble doing that, because most of the oil will remain cool, very few btus are being added to the oil and any oil that heats up will quickly be cooled by the cool oil.
you are also right about hardening tools, if any tool needs it, you bought from the wrong manufacturer.
havent you ever flicked a lit ciggarette into a puddle of gasoline, it will put the ciggarette out. insufficent heat and quick snuffing out in cool liquid. even though it did light the gas in that melgibson movie 'payback' in real life lighting gas with a cigarette is not so easy to do. Dont try it indoors though, indoors is mostly flamable, (cept the stove top) outdoors dirt and rock and concrete arent going to cause trouble.

[Shrub]

These sorts of threads make me cringe a little,

To the OP, well done, welcome to the site,

To the subject,

I cant believe youve rehardened your hand tools and made them brittle,

I assume they are all brittle as you havent mentioned tempering them again,

While im on this subject lets just make it clear, heating metal up and quenching is called hardening, reheating that material to a known tempreture and quenching again to destress the material is called tempering,

If you have a low cabon steel you can add carbon to it to produce a harder surface, this is ONLY done and used on low carbon steel, this is called case hardening,

The method is to useually have a bucket of case hardening powder which is commonly mostly carbon,
You heat the material up until its a bright red and then dunk it in the bucket, leave to cool down in the bucket,
Take the material out the bucket and you will now see that the surface is very rough with bits stuck all over it,
Reheat the material until its a cherry red and then quench it,
You now clean the material up,

To harden a high carbon steel you heat it up to a bright red/yellowy and then quench immediately in cold clean water or clean fresh heavy weight oil, there is little differance in the final surface but i will explain in a minute why use either,
Now you need to clean the surface up to bare metal again and reheat,
Heating to a straw colour (normal to dark yellow) and then quenching again will de-stress the material and remove the brittleness without the hardness,

To soften anything you heat up as much as you can and leave it to cool in air,

Oil versus water,

Firstly no minerals from the oil transpose into the material being quenched, it is true however that oil can give a more even hardening and in some circumstances a higher hardness than water,

You do not use old/used oil, this has contaniments in it that can/will change the surface finish of the material and also its bad for your health causing skin problems or the fumes can cause lung problems,

Water and oil do the same job but oil is used fore the reasons above and water is used because its cleaner and easier,

Water evaporates very quickly and after a couple of quenches an industry needs to re top up the tanks, with oil it evaporates a lot slower,

On pick making theres no reason to use one or the other but water is 100 times more safe and is easier to obtain and dispose of, you cant pour it down the sink dont forget,

Im sorry if ray covered this at all but as always i cant read the big blocks of text,

[Wolfe]

Sorry Rai i was not very spicific to which post i was refering to. My comment was for the silly original poster.
Just for the record i have no degrees in metallurgy nor claim to know all about the subject.
but i do know enough to know this:

you feel the overwhelming need to quench or cool some red hot steel or other non ferrous metals several techniques have been developed over the past few centuries. Learn them and i can guaranty old used motor oil is not going to be on that list.

For a couple centuries or so people with far more experience than most of us have been improving the chemical composition of steels and improving the heat treatments of steels to give us the current tool steel we use today(it really doesnt get much better) but If you do feel the overwhelming need to case harden/temper/caborize your tools at least learn how to do this and take the propor safty procautions.

spring steel and or stainless steel produced picks have enough strength & hardness to preform thier duties very well.fee free to explore other avenues but ferther hardening without tempering probably isnt your best bet.(This would also apply to hand tools also)

thats all im trying to say.
and i hate misinformation,that too
hope this helps
W.

[maintenanceguy]

This can't possibly work. Your picks may end up harder, but not for the reason that you think.

There is no way that you are going to incorporate carbon into the crystalline structure of the iron by letting oil burn on the surface of the metal. If the steel was hot enough, you might...might convince me that you could get some carbon into the surface a few molecules deep but never deep enough to alter the properties of the steel. And since the combustion would be so dirty, you'd probably just incorporate impurities. No biggie though, that few molecules would rub off just sliding the picks in and out of their case.

However, oil quenching is often used to harden steel. It's the rapid cooling, not the carbon in the oil that makes the steel harder. Different steels behave differently but typically, the faster steel cools, the smaller the crystalline structures in the steel are. The smaller these crystals, the harder (more brittle) the steel will be. To get the "right" hardness, you need to know which steel, quench at the "right" temperature, and quench in the "right" liquid.

Google "tempering steel" and I'm sure you'll find charts that let you use the color of the steel to determine when it's the "right" temperature for your application.

Most oil tempering is done around 450 to 600 degrees. If you're catching the oil on fire, you're above the ignition point of motor oil which I'm sure is too hot to temper correctly.

By the way, slowly cooling steel to soften it is called Annealing, tempering is cooling quickly to harden steel.

[snelprobe1313]

OK for the record i did not post any misinformation , i simply left out some info.

To Wolfe Im a blacksmith by trade and when i was asked why would i ever temper my own tools i say this."i temper them because some metals i work with are harder than that of my Tools, OK so in order to shape most metals efficiently my tools need to be harder or equally dense. the same goes for my chisels witch i use for pealing or scraping metal. comon Nails are not hardened their galvanized tats why the bend when you hit them. Also Chisels are not hardened simply because they don't need to be when used on WOOD!!, so i don't see why you would assume they are, You can buy hardened chisels but their more expensive. As far as hammers go you can also buy hardened steel hammers but most of the time their talking about the shaft not the head, about my hammers im talking about 3lb-4lb light shaper/ pointed bevel hammers and 8-12lb flat hammers not your 16-32oz. wal-mart special. So i don't want to hear any more arrogant or ignorant replies as well i don't need your opinion of my knowledge of metals all together. Not knowing anything yourself.

I assume everyone who replied thought i was talking about your average 16-32oz framing hammers. Yes hardening makes metals brittle but with an average 32oz. hammer I can't and I'm sure you can't swing a hammer hard enough, or fast enough to impart the force it takes to break it. witch is around 300-350 ft.Lbs or equal to swinging it around 190mph. The hammers I use are a lot bigger and stronger

I didn't say any thing about the temperature because i posted the thread for homemade picks like the ones made from hacksaw blades simple heating it up till its glowing is good enough for the average DIYer and i don't expect they will have a digital thermo probe lieing around in the junk drore and for tools like hammers the temp needs to be about 1500 degrees and the metal will carbonize at that temp and used oil is the best to use because it has more carbon than clean oil due to its use in your car but screen it before you use it. To clean the metal after you should use acid sulfuric diluted in water works best

now i may be new to the site and understand that i need to prove my self to the other members for my posts to be taken in good confidence.And i appreciate the feedback so Thank you , but I'm not about to let someone who knows nothing about what i post tell me that i posted misinformation. so like i posted on the original post if you have a question send me a private message. Otherwise i appreciate all the feedback ,

And the coloring trick is cool and it works well with thiner metals

[lunchb0x]

i cant say anything about whether it will work or not but it might be a good idea to go through it step by step in your first posts, as said there are a few younger people on here and we gont want them hurting themselfs because something wasnt written out clearly.

personally i would like to get in to making my own tools and hardening them but I dont find it nessasery for picks if you are making them out of something thats already hardened, the only times I have bent my picks is when I have been inpatiant and started getting heavy handed with them.

[snelprobe1313]

I agree , don't get me wrong im not getting willdly out of controle and mad. I just don't want someone who is unexperienced in in the trade telling me, without haveing tested my method, i was wrong. But yes i agree with everyone on the safty issue and i should have used more caution and for that i apologize

[mercurial]

To clean the metal after you should use acid sulfuric diluted in water works best.

I agree , don't get me wrong im not getting willdly out of controle and mad. I just don't want someone who is unexperienced in in the trade telling me, without haveing tested my method, i was wrong. But yes i agree with everyone on the safty issue and i should have used more caution and for that i apologize

I am not a blacksmith or any kind of metallurgist, however, any carborizing that may happen by absorbtion of carbon by quenching in dirty motor oil will be in a microscopically thin surface layer. As mentioned above, this will be so thin as to be insignificant.

You suggest cleaning the picks with dilute sulfuric acid. The way this cleans the metal is by dissolving the thin oxide coating, and then etching into the metal very slightly. This 'cleaning' process will certainly dissolve any thin film of metal with extra carbon from your 'quenching in dirty engine oil'

I am not debating the fact that metals can be hardened by heating and quenching. This is due to deliberate alteration of the crystal structure of the metal, but this idea of carborizing the outer layer of metal by quenching in dirty oil seems questionable to me. Especially if the same metal is then washed(etched) in dilute sulfuric acid - removing any thin coating that may exist.

...Mark