DIY metal hardening

[garnaz 215]

Is it possible to do this as a diy as title says?

 

[mogunner 240]

Sure, the only problem is telling how hard it is. What you have in mind?

[gunfun 3,931]

What metal and how hard and for what purpose. For most steel, get it hot and then quench it in oil will give you a basic temper, but maybe not as good as it started.

 

Some metals can work harden...

 

Some people heat treat their shot before loading too.

[garnaz 215]

The metel is from an old bed frame on one the other is unknown.

It is for bolt hold open for s12.

 

And this is where I catch hell.

I have two different lrbho and one the beak gives after about 50rds and doesn't work as it should.

The other may not need it but just in case.

 

These aren't one of the current that were sold so no calling for help.

I've sent pics to cobra and jack but neither has seen before.

 

What metal and how hard and for what purpose. For most steel, get it hot and then quench it in oil will give you a basic temper, but maybe not as good as it started.

 

Some metals can work harden...

 

Some people heat treat their shot before loading too.

Just motor oil?

[gunfun 3,931]

 

I am no expert this video shows the basics. Get it to Hot Cherry Red then quench it. If you don't temper metal afterward it will be brittle. You are going to need to start with some better steel though. Maybe an old leaf spring would be a good starting point.

[echoside190 127]

Doing a spark test on the metal you intend to use will give you an idea of it's carbon content, thus telling you if it can be hardened and how much. Take the steel to a bench grinder and watch what shape the sparks are that come off of it, if the sparks are straight with no feathering it's a very mild steel and wont be capable of hardening. The more sparkly they look indicates a higher carbon content.

 

 

Not knowing the type of steel you're working with leads to it being a game of trial and error, but if you're wanting to really harden and temper a piece for using pick a high carbon steel and look up how it should be quenched and tempered. I've made a few knives out of 1090 carbon and for heat treating I brought the entire piece to critical (non magnetic) and very quickly quenched it in canola oil.

 

At that point the metal is very hard but brittle so as soon as possible after that point it needs to be tempered. What I did was take a toaster oven with a good oven thermometer and tempered at 400º to a straw color multiple times to relieve stress, bring the hardness down to a more usable level and give it back some of its toughness. The color it turns while tempering lets you know how much you've softened it up.

The best thing to do though would be to buy a sheet of steel that suits the kind of job you need it to do and read up on heat treating that specific alloy to hold up properly.

[gunfun 3,931]

For the amount of time you are investing, getting a small stick of tool steel from a metal supply would be worthwhile. You want a permanent fix, not constant messing with it.

[echoside190 127]

For the amount of time you are investing, getting a small stick of tool steel from a metal supply would be worthwhile. You want a permanent fix, not constant messing with it.

This would be the best approach, for some things it is fun just to make something from a piece of scrap laying around the house into something useful but when it needs to stand up to some real abuse, especially in a firearm, it's always good to know everything about the material you're building with.

[garnaz 215]

Doing a spark test on the metal you intend to use will give you an idea of it's carbon content, thus telling you if it can be hardened and how much. Take the steel to a bench grinder and watch what shape the sparks are that come off of it, if the sparks are straight with no feathering it's a very mild steel and wont be capable of hardening. The more sparkly they look indicates a higher carbon content.

 

 

Not knowing the type of steel you're working with leads to it being a game of trial and error, but if you're wanting to really harden and temper a piece for using pick a high carbon steel and look up how it should be quenched and tempered. I've made a few knives out of 1090 carbon and for heat treating I brought the entire piece to critical (non magnetic) and very quickly quenched it in canola oil.

 

At that point the metal is very hard but brittle so as soon as possible after that point it needs to be tempered. What I did was take a toaster oven with a good oven thermometer and tempered at 400º to a straw color multiple times to relieve stress, bring the hardness down to a more usable level and give it back some of its toughness. The color it turns while tempering lets you know how much you've softened it up.

The best thing to do though would be to buy a sheet of steel that suits the kind of job you need it to do and read up on heat treating that specific alloy to hold up properly.

 

 

 

 

 

 

Thanks guys

EM looks from pic you have it won't be possible with this metal.

 

Will have to see how long they last.

[gunfun 3,931]

EM probably knows a lot more about this than me. You can also get small quantities of things like this off of ebay cheaply sometimes which can be handy for small projects and hobbyists who cannot afford quantities that some metal suppliers sell in.

[garnaz 215]

For the amount of time you are investing, getting a small stick of tool steel from a metal supply would be worthwhile. You want a permanent fix, not constant messing with it.

 

Will look into

 

Thanks for input always good posts

[ShadowFire 220]

I would also go with tool steel.

 

However since I am a machine shop student, hardening is more appealing because of the education factor. And yes oil quenching is an old school way that will indeed harden it. M1 Garand receivers are oil quenched and are actually somewhat harder than an M1A or M14 receiver because M1A/M14 receivers are not oil quenched.

 

Motor oil would likely work, I would not use used motor oil, you will reintroduce potential slag in the metal at the molecular level because of all the stuff in the dirt and grime. I do not recommend cutting oil, it has a carcinogen in it and why most companies keep issuing coolant. Just put it in there quick if you can, you don't want it to ignite on the surface where oxygen is present, just dunk it good.

 

I'm in the process of learning about tempering. What it is and how to do it, etc. Apparently there are some different methods of doing it.

 

In fact I will be screen shotting this topic. Good information and can be applied to all sorts of things made of metal.

[RED333 1,025]

Blood. piss, molten lead, and the good one, mercury.(fumes will kill ya)

All will work to some point to harden steel.

The fun part is how hot ya get the steel.

Just get some tool steel to make you part, just dont brun it with a grinder.

[2manysaigas 14]

Old method was to case harden gun parts by wrapping parts in carbon bearing materials such as bone, leather, horn, and charcoal keeping it red hot for 4-5 hrs in a ceramic sealed (clay?) pot so the carbon bearing material would not burn off. Gave a mottled blue and golden finish. Have heard that some modern day case hardening chemicals are toxic.

 

This is the look with modern methods:

scroll downto third or fourth photo.

http://www.gunauction.com/search/displayitem.cfm?itemnum=9557684

[mogunner 240]

You mention bed frame steel, I've done quite a bit with it but never anything that I consider to be real important...usually just welder or shop carts, just made some swinging targets, made a few collapsible target frames, etc. The problem is finding out exactly what is in it...a lot of them are made from recycled railroad rails and you can seriously screw up cheap tools working with it, you're not going to drill a hole in that stuff with your Walmart drill bits if it is.

 

Look on ebay, I've picked up smaller chunks of tool steel off there quite a bit. I needed to make a firing pin for a Spanish pistol, needed 1/2"x 3" and the smallest chunk I could get through the usual suppliers would have made 32 of them...got a small scrap from a guy on ebay for $7 shipped.

[poolingmyignorance 2,191]

Okay so heres my bit of basic knowlege of tempering and annealing.

 

Tempering is hardening of a steel to a specific hardness. Through heating of the steel untill it's so hot it's no longer magnetic(critical range), then quenching rapidly, in any number of various medium. The specific medium depends on exactly what type of steel your using and what your intended use of said steel is.

An example is as mentioned oil, used motor oil (which has higher carbon content than unsed) water, and even molten salt. I'm sure there are plenty others but those are the basics.

Now these rapid quench techniques will dramaticly harden steel but with hardening comes making it brittle. Now this is where things get a little less DIY freindly.

Annealing: the process of softening steel.

To do this you must heat a steel to below it's critical range, and slowly and controlably decrease the temperature of the steel untill it's back down to room temp.

Now how hot and how long you delay the process of cooling depends on how much hardness you wish to remove from the steel. It's a very specific process that most commerical grade ovens aren't capable. Particuarly achiving a steels critical range. Now you can always set your alarm and start reducing the temp x number of degrees each interval but your talking a several day process in most cases. It can be done at home..but not without some serious ingenuity and research.

Many hobby knife makers build their own ovens, and spend a good amount of cash, and quiet a bit of time researching the formula for what they wish to achive. DIY metal tempering borders on a hobby of it's own. So buying a piece of tool steel is probably still the best option of you. Tool steel is extermely hard to work with and comes in many differnt grades and coatings. If you plan on cutting a piece of tool steel on a mill, you need to invest in some solid carbide TiN coated end mill bits. Or at least soild carbide uncoated.

Edited October 21, 2012 by poolingmyignorance

[DrThunder88 912]

Chances are good that a hobbyist can get good enough results out of 41XX steels using just a torch, some oil, and an oven. I'd heat to non-magnetic, hold it there for a minute or two, quench in oil, scrub the part in very hot water, dry and place it in a preheated oven at 350 degrees F for an hour. If you have a couple cast iron skillets, they can be used as heat wells if they're preheated with the oven and the part is sandwiched between them. After the part has cooled, clean off any scale and use the color guide Echomaker posted to hit the softness/toughness you desire. Weirdly, 41XX series steels experience a dip in toughness if they're tempered above 350 degrees F but are not yet tempered to something like 800 degrees.

 

Anyway, whichever steel you chose to use, research the heck out of it. Info is out there, frequently straight from the manufacturer, on the temperatures you need to hit for hardening and tempering. TempilStiks are a cheap and easy way of gauging higher temperatures and may be readily available at welding supply places.

[socom688 217]

Man this thread is yet another reason why I love this forum! It seems every time I browse this site, I learn something that holds real world practical value. A few friends of mine were wanting to harden a home-made suspension compressor for their cars... this thread would have been majorly useful.

[gunfun 3,931]

Well, these guys are dumping a lot more info than I have to offer.

 

I will add that for so small a part, you can get away without buying a torch. I've done a few things that size just setting them on the stove burner until HCR and tossing them in a pan of water. I know it isn't perfect, but for a part like this, it would work fine.

 

That's what I did to anneal the factory trigger guard before drilling and re-bending. Then I just heated it back up and quenched. Ditto the safeties I added tabs onto. Drilling that steel will kill drill bits. I've got cobalt, but annealing just makes the whole process easier. After re-tempering they were back to their old springy selves.

[Redhunter2486 22]

I've made a few knives, you can use coal in a in a closed metal container in the oven. Depending on how hard you want 2-6 hours about 550, some ovens don't get that hot though. I temper the blade, put it in the coal box in the preheated over for just under 2 hours, the body of the knife will be tempered and the edges would be harder, holding a better edge. You can get steel to the same hardness as cast iron this way but it does get brittle. Sounds like if I were you I'd try to get my hands on tool quality steel though. As fun as blacksmith is I'd limit the importance of what I was doing it on until I was a little more practiced.

[BuffetDestroyer 969]

If you are just getting into this, get a MAPP torch instead of propane ($35-$50 at the hardware store with the fuel). You can still run cheap propane through it, but MAPP burns hotter.

 

This is how many DIY'ers treat AK receivers. Heat area until orange and then dunk. Repeat for critical areas.

 

You can also dunk in soapy water instead of oil as the soap changes the boiling point and quenches faster. Saltwater will also do this, but will typically cause minor surface oxidation on the metal.

 

Test your quality drill bit on annealed steel, then harden it and you will notice that it takes a lot longer to make any headway.

Edited October 22, 2012 by BuffetDestroyer

[Ronin38 2,117]

On a related note, how do I drill a hole in tempered steel? I have an old wakizashi blade that is decent steel (holds an edge fairly well), but the furniture on it is cheap junk. I want to make a new grip for it with 2 pins to make it more usable. I've gently ground the blade down so the handle will now be full-tang, and drilled the first new hole with no problem. The second new hole, at the end of the tang, the drill bit went about halfway through and now I've completely dulled 2 bits trying to finish the hole. I am using a drill press on "medium" speed. I used WD-40 while drilling the first hole, which went fine, so I started with that for the second. When the first bit failed, I bought a new carbide bit and used motor oil to lubricate it. No progress at all.

 

The metal around that area is in the dark blue to light blue area of the chart above, while cold. Should I just try a new hole in a different location?

[poolingmyignorance 2,191]

On a related note, how do I drill a hole in tempered steel? I have an old wakizashi blade that is decent steel (holds an edge fairly well), but the furniture on it is cheap junk. I want to make a new grip for it with 2 pins to make it more usable. I've gently ground the blade down so the handle will now be full-tang, and drilled the first new hole with no problem. The second new hole, at the end of the tang, the drill bit went about halfway through and now I've completely dulled 2 bits trying to finish the hole. I am using a drill press on "medium" speed. I used WD-40 while drilling the first hole, which went fine, so I started with that for the second. When the first bit failed, I bought a new carbide bit and used motor oil to lubricate it. No progress at all.

 

The metal around that area is in the dark blue to light blue area of the chart above, while cold. Should I just try a new hole in a different location?

You can get true carbide bits at a machine tool supply store, like CW Rod, or Bass Tools. If it's just stainless you might get away with a cobalt a with a TiN coating. And get a bottle of quality cutting oil like Tap Magic.

If it still doesn't work, for you send me the blade with hole center dimensionas and I'll mill em' out for ya. Just pick up the shipping.

[Ronin38 2,117]

Thanks, I'll look for those bits! Thank you very much for the offer, too!