temper

All posts tagged temper

So, you want to forge knives… Well, I just started myself, only made a few blades so far. I have learned some information useful to beginners that might not be readily available online, or scattered all over the place. These lessons learned might save you some time, aggravation, even a few dollars.. Follow any advise here at your own risk, I am no expert and forging is inherently dangerous.

About forging: Forging is not just that, hammering a red-hot piece of steel into a blade. You need to consider what else comes into building a knife. A lot of time will be spent grinding, sharpening, and polishing. If using sand paper gives you unpleasant goosebumps, or you cringe at the thought of getting burned or cut, you might want to look into knitting. Heat treating is not as simple as plunging your steel in water. Some knowledge of metallurgy about different steels and what happens to them at different temperatures is a must. Annealing, normalizing, hardening and tempering are important phases in creating a blade. Then you need to make a handle, sheath, and sometimes apply different finishes. Building a knife is a whole process, forging is only part of it.

Forge: I started by building a charcoal forge. It worked, but it is slow and dirty, a pain in the ass, really. Sure, It only cost me $60, and I could have built a better one. Gas however is fast and clean. I bought a $200 forge on Ebay and never looked back. The next one will have a round shape though, and be covered with refractory cement instead of KAOWool. A round forge body creates vortexes resulting in a more even temperature and probably gas saving. With a hard refractory coating, you will never breathe dangerous ceramic fibers.. Coal is another good option, also dirty, but better in my opinion than charcoal. See my gas forge here.

Steels: Many beginners will try to find some scrap steel at the junkyard. You might get lucky finding what you want, but you might not. Spending hours hammering steel to find out that it won’t harden is no fun. I just ordered six 3/16 x 1” x 60” bars of 1080 from Admiral Steel for about $90 (with shipping)! That is enough to make from 30 to 40 large knives. Less than $3 per knife. Mystery steel is like mystery meat, you really don’t know what’s in it and most of the time, it doesn’t turn out to be that good. 1075-1080 is probably the best steel to start with. It is a simple steel, easy to heat treat and forge. You can temper it in a kitchen oven at 450F. Tool steels and other higher carbon steels require better temperature control and higher tempering temperatures, around 550-600F. It isn’t worth my time fishing for scrap in a junkyard. I would probably often have to discard half-finished blades, so the savings are really not significant enough. Buy good steel, pick one kind, learn it well, you’ll get consistent results allowing you to refine your process. More on steel selection.

Heat Treatment Anneal every time you stop working for the day. Normalize three times before hardening. Use a magnet to determine when the steel has turned to austenite and is non-magnetic. Go slightly higher, and let the blade soak for ten minutes at that temperature. If you forge or heat-treat too hot, your steel will decarbonize. Quench in warm oil (140 to 160F). Cold oil will actually not cool your blade as fast. Avoid motor oil, it’s too thick. Thin oil, such as ATF or thin mineral oil is better. Don’t move the blade sideways while it cools, but front and back. If you want to create a hamon by differential clay hardening, cover the back of the blade with a refractory like Satanite (1/8” thick layer). Temper immediately after hardening, three times one hour at 450F. If you use a different steel than 1060-1075-1080, find out what the numbers are, don’t just guess..

Anvil: I bought a cast iron anvil at Harbor Freight. It is way too soft! Here is when a trip to the junkyard might save you money. A 100Lbs hardened steel anvil will cost you $400 to $600. Find any piece of steel with a flat surface, as heavy as you can carry. Secure it to a solid base, so that you can forge standing up. Thanks to my friend Phil and his father at Seaboard Steel, I was able get a heavy piece of steel which originally was a jaw that grabs giant steel plates. It must be heat-treated because it is very hard. We welded it to an I-beam and a half-inch steel base.

Click on the image to enlarge..

Hammer and tongs: Almost any hammer will do (you might want to put a nice smooth finish on it’s face), but you need tongs to grab your blades. I started with a pair of wise-grips, but they are too short and awkward to use. Having a piece of red-hot steel fly out when you hit it is pretty scary. Don’t ask me how I know.. (well, I still have one scar on my ankle..) Start by forging tongues. It is easier than forging a blade, and you will need them anyway.

Click on the image to enlarge..

Not the best looking ones, but they work just fine..

Safety: Wear heavy leather gloves and clear eye protection (clear to see steel color). I have a welding jacket with leather sleeves that’s perfect for forging. Make sure nothing close to the forge can catch on fire. That includes your propane hose in particular! Wear a respirator when grinding or changing your ceramic fiber forge insulation. Don’t forget, you’re building knives, they can get really sharp! Blades can fly off your hands while grinding, specially when using buffing wheels. You must be conscious of safety all the time. You don’t want to end-up in the hospital or dead because of a hobby!

Information: It is easier to start with some help. Browse the following forums online:

Document you progress. You might discover that a blade you forged displays great characteristics after some use, and not remember how you made it..

I highly recommend Wayne Godard’s $50 Knife Shop book:


Wayne Goddard’s $50 Knife Shop, Revised
And Tim Lively’s DVD:


Knifemaking Unplugged

I will add to this article once in a while as I discover new tips or pitfalls to avoid. Anyone with more experience than myself, that’s almost anybody able to forge a decent knife at this time, please add any advise for beginners you may have in the comments section below. Many thanks to the members of bladeforums.com for their feedback on this article!

After weeks of consideration and research on the web, I finally decided to buy a katana. Not a cheap wall-hanger, but a practical sword, forged by hand and differentially hardened. I am very familiar with knives, even started to forge my own. Swords however are mostly unknown to me. Why would a grown man buy a sword you may ask, well, I have a few reasons, and they have nothing to do with the “cool” factor. Swords are not toys, but deadly weapons. I place them in the same category as handguns and rifles. I came to believe that they are one of the best home defense weapons available. My interest in knives came from the staggering number of designs found for such a simple, primary tool. Metallurgy, the forging and hardening processes have always fascinated me. I have barely scratched the surface of that art, but I can certainly appreciate the skills it takes to forge a blade longer than a few inches, then harden and temper it properly. My life-long interest and practice of the martial arts also influenced my decision. I have long ago found out that most Asian disciplines only work in their context. Russian Systema however works in any circumstances and can make use of any weapon. Give me a frying pan and I’ll be immediately efficient with it using Systema principles. A sword, though presenting some challenges, shouldn’t be too much trouble. Of course, I will use a dull one or bokken for practice. Other sword designs were interesting, but the Japanese katana in my opinion is the best sword. It is light, razor sharp, and simple in design. Nobody wears armor these days, so a heavier sword would make little sense. The way these swords are made is also fascinating. Even if you have no interest in swords, you can’t but admire the dedication and skills of Japanese sword-smiths in their pursuit of perfection. I never get tired of watching the following documentary from National Geographic:

[kml_flashembed movie="http://www.youtube.com/v/ko9vR2_ptlA" width="425" height="350" wmode="transparent" /]

I can’t pay three highly skilled artisans for three months to forge me a blade, so I have to accept some technological shortcuts. Modern steels like 9260 Silicon Alloy Carbon Spring Steel are even better than traditional tamahagane. It’s not traditional of course, but much cheaper. The folding process becomes superfluous, since the carbon content of modern steel is constant throughout the material. I would love a folded blade, but the cheapest ones, forged in China, start at around $1000. More than I am willing to spend for a first purchase. A San-Mai construction like my Cold Steel Master Tanto would be desirable too, but simply too expensive. There is one feature I really want however, and that is a differentially, clay-hardened blade. This process of covering the back of the blade with thick clay before quenching in water produces a very hard edge and a soft back (watch video above). This way, a sword will bend but not break, while still holding a razor-sharp edge. It also produces a visible line of hardness called the hamon. Most replicas have a fake one, acid-etched on the blade. I can’t accept “fake” anything, so my choice becomes fairly limited for an affordable real sword. Thanks to companies like CAS Hanwei and Cheness Inc., real forged blades from China are available, starting at around $160 for something that won’t come apart in your hands and take a lot of abuse before breaking. Shell-out $200 to $300 and you get a serious tool. My choice is the Kaze Ko-Katana. With a 21-inch blade, this katana is about seven inches shorter than a regular sword. These swords are also called chisa katanas, and are easier to use in tight places. Here is another review of the Kaze (watch the cutting test video). I got a 10% discount and ordered mine for less than $200, with free shipping.

Proceed to the full review