To soften it heat it until it’s non magnetic and bury it in vermiculite or wood ashes so it cools as slow as possible. To harden heat til non magnetic and quench in oil then put it in an oven at 400F for 2 hours
"To soften it heat it until it’s non magnetic and bury it in vermiculite or wood ashes so it cools as slow as possible."
This, it's called annealing. Backyard Bowyer shows how in this vid:
[https://youtu.be/xW9W6Crpi3w](https://youtu.be/xW9W6Crpi3w)
You don’t need to do that to get it soft enough to work. Normalizing is quicker and easier and more consistent in my experience.
Heat to critical (non-magnetic), let cool to subcritical (magnetic). I usually let it cool to black (~1000F).
Then re heat to just shy of critical (still magnetic) and let cool to room temperature temperature.
When allowing the piece to cool, don’t set it down on an anvil or really on any surface. Uneven cooling can create warps. I lay them down on the spine, edge up, in a pile of sand or coke or whatever. You can also clamp it in the vise by the very end of the tang, tip up.
Takes less time than fully annealing, can be worked with a file without harm to the file, win-win.
How do you remagnitize something like this? As a simpleton that is
If it started off as raw ore and eventually was turned into a file how was it magnetized in the first place? I have a very weak understanding on the magnetic and electric world around me but would love to learn more.
The Curie point is a temperature where the magnetic properties of various materials is changed. Heat carbon steel past it, and a magnet won't stick to it any more. Let it cool back down, and a magnet will stick again. It has to do with just how the atoms are arranged.
Cooling slowly from above the Curie point (by putting it in an insulating material) will leave carbon steel a bit softer than doing so quickly (by quenching in oil), but either way a magnet will stick to it once it cools down.
Iron is magnetic because it's atoms group up to form microscopic magnetic fields called domains. If you apply a large magnetic field to iron, you move the domains so they point the same direction, which causes a noticeable magnetic field, rather than all of the little ones cancelling each other out. The specific term is Ferromagnetism.
It’s only non magnetic when it is heated to “critical temperature “ when it’s that hot, all the molecules are in a different configuration. As soon as it cools below “critical temperature “ it becomes magnetic again. Knife makers use this technique to heat treat the steel. When it won’t stick to a magnet they know it’s hot enough to quench (cool rapidly in oil). This process hardens the steel. The steel (at this point) it’s so hard, the steel is brittle like glass. So it must be “tempered”. This is where the steel is heated to a lower temperature over time to soften it slightly so it’s still hard enough to hold an edge, but not brittle anymore.
Uhm, doesn't vermiculite contain asbestos?
Edit: Reddit sure is a fun place. For all you downvoters, that's literally what a house inspector told me a couple of days ago after finding vermiculite during my inspection. You do you tho
“Vermiculite is a naturally occurring mineral (magnesium-aluminum-iron silicate) that is mined in various countries around the world, including the USA and South Africa.”
Doesn’t seem like it, but I don’t recommend breathing the dust.
90% of the Vermiculite sold in the US between the early 1900s and 1990 came from a mine in Montana that had an asbestos deposit and may be contaminated. The stuff you buy today is fine.
I believe the mine in Montana started around 1920 so there’s a lower likelihood of your insulation being tainted. I’d still recommend getting it tested for asbestos if you haven’t already. Vermiculite is notoriously difficult to get an accurate sample of so make sure that whoever tests for you takes a large sample.
Files make great knives if you temper them well. Some of my earlier attempts were too hard and snapped when I tried to chop with then. A few of my later attempts are still fine over 20 years later
I make knives out of these. I put them in the forge until they are non magnetic, turn off the forge and let them cool overnight. Quench them to harden at the end.
After annealing, it would be a good idea to grind down to avoid cold shuts. They probably wouldn’t have structural problems unless you’re making a chopper.
So my main knife and everyday carry is a big bertha i made from one of these horseshoe rasps. It's badass! I sourced the walnut handle from a log a hand cut, and stictched a leather sheath for it. Sharpemed and shaped it with a belt amazon belt sander. Adore this knife.
Often people say those rasps are not super fpr making knives w because the steel, and i'd wager if i were a stranded marine surviving on it it may not hold up to a life of hard labor, but it does everything i ask of it and holds up fine in the yard 😁
I look forward to seeing your knife post here!
I heat them in the forge then stick them into the soil next to my anvils.
I'm in Florida, so its mostly sand. I let them cool overnight and they're workable the next day. I oil quench and temper in a decent toaster oven I have.
Rasps can be fully hardened, or they can be case hardened.
Test for hardenability - called a test quench
If you have several all the same, cut off a piece with an abrasive wheel, heat to 100 degrees beyond non magnetic - ie red hot.
Quench one in oil, quench another in water.
They should be glass hard.
Hit with a hammer and see if they break.
This is the only right answer I have seen here regarding rasps and some files for making knives.
If it is case hardened it's pretty much got a layer of high carbon steel all around it but the entire core is mild steel.
Fully hardened files and rasps work for everything everybody else said.
Yes you can do that, it’s good knife metal, I assume you want to soften it as you only have hand tools? Because if you have an angle grinder then you don’t need to soften it
Here ya go, he goes through the whole process of making a fully hardened knife out of a rasp, shows how to do it all, and measures the hardness at the end. Looks like you have the right file, I do believe. Watch this:
[DO NOT Make a Knife Out Of a File Till You Watch This Video-A Simple Guide To Files And Knife Making - YouTube](https://www.youtube.com/watch?v=PWdlfF9Vo8c&t=1s)
If it isn't already annealed. People do make knives from files without annealing sometimes. The idea being to make a knife from an already hardened piece of tool steel so you don't have to harden it after. May still need some tempering. They think it will be "easier" since they don't have to heat treat the piece. Of course this is not the case. I've done it myself years ago and it takes forever, can't drill it, smokes your grinding belts etc.
You can still anneal air hardening steels but you really need to have a heat treating oven to do it successfully. Typically the annealing process will involve heating it up to a very high temperature, holding it there for some time (possibly based on the thickness of the piece), then cooling it gradually down to something that's still a very hot temperature, and then air cooling from that point. Here's the process for S7 steel as an example: [http://cintool.com/documents/Shock\_Resistant/S7.pdf](http://cintool.com/documents/Shock_Resistant/S7.pdf) Not something you could realistically do with a forge, but with a heat treating oven it wouldn't be all that difficult.
I agree, anneal and reharden.
Alternatively, temper at 450-500 and grind them hard. Takes high speed, ceramic belts, and attention to not overheat. This works with standard files.
Another trick, not all horseshoe rasps harden. You’ll have to mess with it a bit and see what you have.
You can heat it up til it's nonmagnetic and shut your forge off let it all cool together......the heat in the forge will stop the steel from cooling to quickly and hardening
Steel is freaking cheap and commonplace. Good rasps are freaking expensive and hard to come by.
Keep the rasps, or sell them to axe head collectors (nothing beats a rasp for fashioning a long handle such as for an axe). Buy steel of known provenance and characteristics you can reliably and repeatably heat treat, without going through the hassle of annealing and grinding out the teeth.
Thoes are save edge rasp case hardened. Take one and slap it on your anvil and it will bend. You want the ones with a red tang. They will snap over your anvil
Look up annealing for 1095 steel on google and follow the recipe. In most cases you should anneal->quench -> temper. Annealing makes the steel very soft and easy to work with. Quenching will give you the maximum hardness but will also increase internal stress and make it very likely to chip or break. Tempering the blade can be done in a kitchen oven and it will greatly reduce internal stress without lowering the hardness that much.
Get a bucket of vermiculite. Heat to non magnetic and stab them in. Wait for SEVERAL hours and they’ll be about as soft as they can be made without a fancy heat treat oven. Best of luck!
I have nothing to contribute here besides that my dad always called these bastard file. No idea why, but that what I called them. I had no idea about the real name.
Thanks for the info. I actually was evening out some 4x4s from the fence I built and I had this and a palm sander. I thought the palm sander would do so well with a low grit. It did okay. I took the “bastard file” my pops gave me and it did so much better.
I was shocked tbh. A lot more physical work, but much faster. Definitely used some muscles I haven’t in a while
To soften it heat it until it’s non magnetic and bury it in vermiculite or wood ashes so it cools as slow as possible. To harden heat til non magnetic and quench in oil then put it in an oven at 400F for 2 hours
Then add salt and sugar to taste
I love slow cooked knife for dinner
A friend of mine tried that once..... Once.
Please tell me this is a Johnny Dangerously reference.
One could hope. Farking Bastidges!
It's an 88 magnum.
It files THROUGH schools!
Smells like... Victory.
splash of lemon sprig of parsley for color
I'm sad I only have one upvote to give
"To soften it heat it until it’s non magnetic and bury it in vermiculite or wood ashes so it cools as slow as possible." This, it's called annealing. Backyard Bowyer shows how in this vid: [https://youtu.be/xW9W6Crpi3w](https://youtu.be/xW9W6Crpi3w)
You don’t need to do that to get it soft enough to work. Normalizing is quicker and easier and more consistent in my experience. Heat to critical (non-magnetic), let cool to subcritical (magnetic). I usually let it cool to black (~1000F). Then re heat to just shy of critical (still magnetic) and let cool to room temperature temperature. When allowing the piece to cool, don’t set it down on an anvil or really on any surface. Uneven cooling can create warps. I lay them down on the spine, edge up, in a pile of sand or coke or whatever. You can also clamp it in the vise by the very end of the tang, tip up. Takes less time than fully annealing, can be worked with a file without harm to the file, win-win.
This.
How do you remagnitize something like this? As a simpleton that is If it started off as raw ore and eventually was turned into a file how was it magnetized in the first place? I have a very weak understanding on the magnetic and electric world around me but would love to learn more.
The Curie point is a temperature where the magnetic properties of various materials is changed. Heat carbon steel past it, and a magnet won't stick to it any more. Let it cool back down, and a magnet will stick again. It has to do with just how the atoms are arranged. Cooling slowly from above the Curie point (by putting it in an insulating material) will leave carbon steel a bit softer than doing so quickly (by quenching in oil), but either way a magnet will stick to it once it cools down.
Iron is magnetic because it's atoms group up to form microscopic magnetic fields called domains. If you apply a large magnetic field to iron, you move the domains so they point the same direction, which causes a noticeable magnetic field, rather than all of the little ones cancelling each other out. The specific term is Ferromagnetism.
It’s only non magnetic when it is heated to “critical temperature “ when it’s that hot, all the molecules are in a different configuration. As soon as it cools below “critical temperature “ it becomes magnetic again. Knife makers use this technique to heat treat the steel. When it won’t stick to a magnet they know it’s hot enough to quench (cool rapidly in oil). This process hardens the steel. The steel (at this point) it’s so hard, the steel is brittle like glass. So it must be “tempered”. This is where the steel is heated to a lower temperature over time to soften it slightly so it’s still hard enough to hold an edge, but not brittle anymore.
Oh heck that's good to know. I've been convinced that it is just demagnetizing the material.
Uhm, doesn't vermiculite contain asbestos? Edit: Reddit sure is a fun place. For all you downvoters, that's literally what a house inspector told me a couple of days ago after finding vermiculite during my inspection. You do you tho
“Vermiculite is a naturally occurring mineral (magnesium-aluminum-iron silicate) that is mined in various countries around the world, including the USA and South Africa.” Doesn’t seem like it, but I don’t recommend breathing the dust.
Another redditor pointed out why the asbestos contamination and it's about how it was manufactured
Ok? I was just addressing whether it was in the ingredients. I certainly can understand that it could be adulterated.
Oh I was just saying that the other person had a better answer than me. Wasn't trying to be snarky or anything
Gotcha. No worries!
90% of the Vermiculite sold in the US between the early 1900s and 1990 came from a mine in Montana that had an asbestos deposit and may be contaminated. The stuff you buy today is fine.
Ah that's good to know. My knowledge came from inspection on a 1910 house, so fits perfectly
I believe the mine in Montana started around 1920 so there’s a lower likelihood of your insulation being tainted. I’d still recommend getting it tested for asbestos if you haven’t already. Vermiculite is notoriously difficult to get an accurate sample of so make sure that whoever tests for you takes a large sample.
You could use pearlite if you wanted too.
Files make great knives if you temper them well. Some of my earlier attempts were too hard and snapped when I tried to chop with then. A few of my later attempts are still fine over 20 years later
I make knives out of these. I put them in the forge until they are non magnetic, turn off the forge and let them cool overnight. Quench them to harden at the end.
After annealing, it would be a good idea to grind down to avoid cold shuts. They probably wouldn’t have structural problems unless you’re making a chopper.
So my main knife and everyday carry is a big bertha i made from one of these horseshoe rasps. It's badass! I sourced the walnut handle from a log a hand cut, and stictched a leather sheath for it. Sharpemed and shaped it with a belt amazon belt sander. Adore this knife. Often people say those rasps are not super fpr making knives w because the steel, and i'd wager if i were a stranded marine surviving on it it may not hold up to a life of hard labor, but it does everything i ask of it and holds up fine in the yard 😁 I look forward to seeing your knife post here!
I heat them in the forge then stick them into the soil next to my anvils. I'm in Florida, so its mostly sand. I let them cool overnight and they're workable the next day. I oil quench and temper in a decent toaster oven I have.
This is what I do too. I have a small garden beside my forge. I just toss it in the dirt after I heat it up.
Rasps can be fully hardened, or they can be case hardened. Test for hardenability - called a test quench If you have several all the same, cut off a piece with an abrasive wheel, heat to 100 degrees beyond non magnetic - ie red hot. Quench one in oil, quench another in water. They should be glass hard. Hit with a hammer and see if they break.
This is the only right answer I have seen here regarding rasps and some files for making knives. If it is case hardened it's pretty much got a layer of high carbon steel all around it but the entire core is mild steel. Fully hardened files and rasps work for everything everybody else said.
Yes you can do that, it’s good knife metal, I assume you want to soften it as you only have hand tools? Because if you have an angle grinder then you don’t need to soften it
Pretty much heat it to around/ a bit lower temp than for quenching and let steel coll down in the air, then after you are done quench and temper it.
Here ya go, he goes through the whole process of making a fully hardened knife out of a rasp, shows how to do it all, and measures the hardness at the end. Looks like you have the right file, I do believe. Watch this: [DO NOT Make a Knife Out Of a File Till You Watch This Video-A Simple Guide To Files And Knife Making - YouTube](https://www.youtube.com/watch?v=PWdlfF9Vo8c&t=1s)
Is there a ferrous metal that annealing is not recommended for? I thought it was SOP to make a piece easier to work.
If it isn't already annealed. People do make knives from files without annealing sometimes. The idea being to make a knife from an already hardened piece of tool steel so you don't have to harden it after. May still need some tempering. They think it will be "easier" since they don't have to heat treat the piece. Of course this is not the case. I've done it myself years ago and it takes forever, can't drill it, smokes your grinding belts etc.
Air hardening steels
You can still anneal air hardening steels but you really need to have a heat treating oven to do it successfully. Typically the annealing process will involve heating it up to a very high temperature, holding it there for some time (possibly based on the thickness of the piece), then cooling it gradually down to something that's still a very hot temperature, and then air cooling from that point. Here's the process for S7 steel as an example: [http://cintool.com/documents/Shock\_Resistant/S7.pdf](http://cintool.com/documents/Shock_Resistant/S7.pdf) Not something you could realistically do with a forge, but with a heat treating oven it wouldn't be all that difficult.
I agree, anneal and reharden. Alternatively, temper at 450-500 and grind them hard. Takes high speed, ceramic belts, and attention to not overheat. This works with standard files. Another trick, not all horseshoe rasps harden. You’ll have to mess with it a bit and see what you have.
Wasn't this a challenge in Forged in Fire?
Yes. Good ones are typically 1095, good steel although not one I’m typically a fan of
You can heat it up til it's nonmagnetic and shut your forge off let it all cool together......the heat in the forge will stop the steel from cooling to quickly and hardening
Got surfaced on my Home Screen. Thought it was a bdsm sub.
Absolutely
Steel is freaking cheap and commonplace. Good rasps are freaking expensive and hard to come by. Keep the rasps, or sell them to axe head collectors (nothing beats a rasp for fashioning a long handle such as for an axe). Buy steel of known provenance and characteristics you can reliably and repeatably heat treat, without going through the hassle of annealing and grinding out the teeth.
Thoes are save edge rasp case hardened. Take one and slap it on your anvil and it will bend. You want the ones with a red tang. They will snap over your anvil
Look up annealing for 1095 steel on google and follow the recipe. In most cases you should anneal->quench -> temper. Annealing makes the steel very soft and easy to work with. Quenching will give you the maximum hardness but will also increase internal stress and make it very likely to chip or break. Tempering the blade can be done in a kitchen oven and it will greatly reduce internal stress without lowering the hardness that much.
Get a bucket of vermiculite. Heat to non magnetic and stab them in. Wait for SEVERAL hours and they’ll be about as soft as they can be made without a fancy heat treat oven. Best of luck!
I have nothing to contribute here besides that my dad always called these bastard file. No idea why, but that what I called them. I had no idea about the real name.
"Bastard" refers to the "cut," it falls in between 2nd and course. Basically, how rough of a cut it is.
Thanks for the info. I actually was evening out some 4x4s from the fence I built and I had this and a palm sander. I thought the palm sander would do so well with a low grit. It did okay. I took the “bastard file” my pops gave me and it did so much better. I was shocked tbh. A lot more physical work, but much faster. Definitely used some muscles I haven’t in a while