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Files and Rasps for Blades - Mark Reich - 12-11-2017
Gentlemen,
In response to a popular question of trying to make knives out of old files, I feel we should have easy access to this specific topic. Wal-la, here we go!
Many people use old files for their first attempts of shaping a blade. Some guys use nothing but old files, or rasps and make lots of knives. They look kinda neat when you don't grind all the checkering off. Actually, just buying a new file or rasp is still a pretty cheap-n-easy way to obtain a pre-hardened blank, but there are MUCH better options.
Grinding hardened steel is a chore, and it gets a lot trickier as the bevels get thinner. It's super easy to overheat the edge, or at least the tip. You may not even be grinding close to the edge, but the heat generated will flow to it's easiest escape route- the thin part. You will toast your first few blades, especially when you progress to finer abrasives. Files are brittle, with huge grain size too. They aren't heat treated to be knives, and it darn sure will show. At best, you'll drop it and it will break. At worst, you may be needing it to survive.
I would highly recommend buying simple steel bar stock instead. "10 series" tool steel is inexpensive and easy to heat treat. Something in the range of 1045 to 1075 would work well. You can buy annealed (soft) bar stock in any practical size, so getting a stick of 1/8" to 3/16" thick by 1" to 1 1/4" wide would save you a ton of work and worry. It doesn't matter how hot it gets while grinding. It's easy to harden when you're done grinding, and it's easy to temper in your kitchen oven after it's hardened.
Honestly, I would never consider or recommend using files without annealing them, then harden and temper after grinding. You're still guessing at what steel your file is made of, so heat treating would be much more hit and miss.
Since heat treating is the soul of a blade, there should be no guesswork involved. Properly heat treated low carbon steel will perform much better than Japanese Aogami Super Blue, or any other fancy steel, or any Unknown steel, without the proper heat treat, or at least something close.
Starting out right is way more than half the battle, and I'd be horribly remiss for not saying so. Making knives ain't easy. Spending time making something that looks like a knife but acts like an icicle is pretty easy, but not particularly satisfying.
If you choose a steel that carries the properties you're looking for, sending it out for The Perfect HT, tailored to your specific application, is a snap. It's also much less aggravating than spending considerable time and energy grinding yourself a noodle out of steel.
KNOWN steel is easy to find, even in the right size. If you choose a regular carbon steel, you can probably heat treat it yourself, and come out with a very usable tool.
RE: Files and Rasps for Blades - Jan - 12-11-2017
Mr. Mark, thanks your post. I was expecting your statement to this important topic.
The forging steel bar stock for knife making is now offered by Amazon also.
E.g. 1080 steel, made in US:
https://www.amazon.com/Forging-Steel-Barstock-Knife-Making/dp/B01JGVOX8S/ref=pd_sim_328_5?_encoding=UTF8&pd_rd_i=B01JGVOX8S&pd_rd_r=ZNCE944HG775DXTKZMQE&pd_rd_w=JEXnq&pd_rd_wg=lDxmC&psc=1&refRID=ZNCE944HG775DXTKZMQE
I have access to Swedish martensitic stainless steel Sandvik 12C27. Do you think it is suitable steel for home forge experimenting?
Jan
RE: Files and Rasps for Blades - Mark Reich - 12-11-2017
Thank you Mr Jan, it's always good to know we are on the same page.
I've always been impressed with Swedish steel, and I've never heard anything that might make me think otherwise. I've actually been using it all my life. My very first fixed blade was a regular small Skandi in a leather sheath. It fit my 5 year old hand well, which is probably the exact reason my Grandad handed it down to me. Sure wish I still had it, but I grew into bigger knives.
Sandvik stainless knife steels have always met high standards, especially for the price, which continues to this day. I've never heard anything but praise for their ability to take a very keen edge, which always means clean, fine grain steel.
There are a handful of Sandvik steels that are fairly common in high grade Knives, and 12C27 might be the best all around blade steel. I think it would be very difficult to tell much difference in these with similar designations and chemical makeup. HERE is a good comparison chart, but with different heat treating, the differences can be minimized. The newest one I hear most about, 14C28N, is not much different than the others. A little harder or a little tougher than 12C27, depending on HT. In hands on comparisons I've read they are hard to tell apart, but 14C28N is often compared to VG10, which is one of my favorite steels.
I don't forge any stainless, so I'm sorry to be of little help there. Usually this type of steel comes in Exact sizes, which is geared more toward stock removal or stainless damascus.
I would not hesitate to use Sandvik for pattern welded stainless, and I'd love to hear your thoughts on forging it!
RE: Files and Rasps for Blades - Jan - 12-12-2017
Mr. Mark, thanks for your detailed answer, appreciated.
My problem is not steel but the kiln. Many, many years ago I have built an electric enamelling furnace, which is probably no more used. I am wondering if it would be possible to tune this furnace to higher temperatures, because it was designed only for some 900 °C (1650 °F).
It might be easier to build a new electric kiln furnace designed for knife blades. I still have several heating elements which could be used. The heating elements can be used up to 1200 °C (2200 °F).
[attachment=356]
My wish is to build a versatile kiln, initially for two blades only, but with an option to expand it in the future by adding several refractory bricks and heating elements.
My shop is in the basement and for this reason I would like to avoid open fire heating.
Jan
RE: Files and Rasps for Blades - Mike Brubacher - 12-12-2017
It looks as if there are already a couple of good questions on the table for you Mark so I'll throw mine on the pile as well. I've managed to accumulate a fair collection of old metal files myself. As you know, they can be picked up at little expense at auction. I'd guess that most of mine date from the 20's to the 50's. What would be your best guess on the type and quality of the steel they are made from? Is it possible to detemper them and then harden/temper again? Seems as if something useful should be made from them. They harken back to an era when men were men you know.
RE: Files and Rasps for Blades - wadebevan - 12-12-2017
I will throw in my .02 here.
My first knife was made from an old 1.25" wide file I found in a random box.
Mark's comment of, "Spending time making something that looks like a knife but acts like an icicle is pretty easy, but not particularly satisfying.", is pretty much where this knife ended up.
Mark is also spot on regarding the difficulty/time/heat sensitivity of material removal on hardened files.
They turn dark blue really fast on the thin parts, and usually when you weren't looking.
There are plenty of good heat treating shops to do the magic.
Personally, the heat treating was something I really wanted to play with and learn about. And glowing red metal is fun!
Could be interesting to anneal and re-HT files, but the unknown of the base metal could end up frustrating.
I've seen videos on youtube of some semi-famous knife maker in that uses exclusively old files. She heat treats them in her shop.
The left on checkering is a pretty cool look.
RE: Files and Rasps for Blades - Ken S - 12-12-2017
I have a set of the Popular Mechanics Workshop Encyclopedia. It is probably older than I am. I love the way those old guys could make things out od tin cans, old car springs, etc.
However, I must admit that if I was going to go through all the work of making a knife, I would spend a few bucks for a good piece of steel.
Ken
RE: Files and Rasps for Blades - wadebevan - 12-12-2017
Reminds me of my apprentice days in a machine shop under the mentorship of a tool maker.
That guy could turn old files and old drill bits into perfect cutting tools just eyeballing the complex angles.
Makes me feel sort of lame complaining about my perfectly ground carbide tipped cutting tools these days!
RE: Files and Rasps for Blades - Jan - 12-12-2017
(12-12-2017, 10:08 AM)ike Brubacher Wrote: It looks as if there are already a couple of good questions on the table for you Mark so I'll throw mine on the pile as well. I've managed to accumulate a fair collection of old metal files myself. As you know, they can be picked up at little expense at auction. I'd guess that most of mine date from the 20's to the 50's. What would be your best guess on the type and quality of the steel they are made from? Is it possible to detemper them and then harden/temper again? Seems as if something useful should be made from them. They harken back to an era when men were men you know.
Mike, if your files where manufactured before summer 1945 than it is so called low-background steel which is not contaminated by radioactive isotopes. Some very sensitive instruments require such a low-background steel.
The first atomic test, the Trinity test conducted on July 1945 and following nuclear explosions, released radioactive dust which was globally embedded into the steel giving it very weak radioactive signature.
Since 1963 the background radiation level is decreasing, but radioactive cobalt still contaminates current steel production because of recycling contaminated scarp steel.
The main source of low-background steel, besides your file collection, is ships that were constructed before the Trinity test, most of them the scuttled German World War I battleships.
Jan
RE: Files and Rasps for Blades - Mike Brubacher - 12-12-2017
Well isn't that something Jan! That explains why my wife says that I have a certain "glow" about me after handling the files.
I went past that site in New Mexico on a motorcycle ride a couple of years ago. Went past the VLA telescope, the Trinity test site and the spot where Billy the Kid shot Sheriff Brady. All in the matter of a hundred miles or so. Billy was just a little ahead of his time. These days, he could get elected to...whoops, just about forgot. Not on the BESS Exchange!