Misconseption about HSS vs. High carbon

[alexkuzn]

My other hobby is knife making. Knife making community is somewhat paranoid about finding the "best" steel. Many knife makers or just knife lovers do very extensive research and testing. Some steel making companies also publish cutting properties of their steel.
I've been studying steel properties and following all the ongoing research and test results for last 4 years and want to share some of my knowledge with fellow pen makers.

The most common myth among wood turners is that High Steel Speed "needs less sharpening than High Carbon Steel" This is absolutely not true!!!
Most High Carbon Steels(O-1, D-2 etc.) when properly heat treated will easily outperform M2 - most common HSS steel used for chisels.
Also High Carbon Steel is easier to sharpen than HSS. BUT if you overheat High Carbon Steel you will anneal it and it'll loose some hardness.

So the only advantage of HHS is that you can overheat it without loosing hardness.

There are some other very good new steels for cutting tool. For example CPM 10V, which I use for my knives. It's highly wear resistant and will keep a sharp edge MUCH longer than any HSS. But it's harder to sharpen and you can't overheat it or it'll loose some hardness.

What's important for any cutting tool other than a good steel is proper heat treatment. Any good steel can be screwed up up by bad heat treatment and common High Carbon Steel will have excellent cutting quality with proper heat treatment.

Heat treatment process can include:
Cryogenic treatment will get you about 2 extra Rockwell points without loosing toughness.
Tempering 2-3 times instead of one that positively affect steel properties.

 

[leehljp]

Thanks for this information. I do have one request: Can you give overview of how to temper common HCS in a small home shop setting? I watched my dad doing this back in the '50s and early '60s, but never tried it. I also remember him dipping steel hot (at times) in a bucket of oil and sometimes water.

How much do you cool it down or hold it in the water or oil? What is the difference in using oil versus water?

What does the color of the metal tell you? brown versus blue when heating?

I think this would be a great help for some people here. Sharing your experience is greatly appreciated too!

 

[amosfella]

Very big can of worms that is about to be opened leehljp.
Every one who does this has their own privately developed method, and they all think their way is best.........
My way is best though.

 

[leehljp]

Very big can of worms that is about to be opened leehljp.
Every one who does this has their own privately developed method, and they all think their way is best.........
My way is best though.

Maybe I would be better off looking it up on wikipedia! :biggrin:

Seriously, you are probably right. A few months ago, during a trip in SE Asia I read about colors in sharpening. Shortly after that, I spent a few days with a friend that makes knives (in the Philippines) and he contradicted much of the article that I had read. Boy, did that mix me up!

 

[pipecrafter]

Thanks for this information. I do have one request: Can you give overview of how to temper common HCS in a small home shop setting? I watched my dad doing this back in the '50s and early '60s, but never tried it. I also remember him dipping steel hot (at times) in a bucket of oil and sometimes water.

How much do you cool it down or hold it in the water or oil? What is the difference in using oil versus water?

Like alxkuzn, one of my hobbies is making knives. (actually, a paying hobby)

What you use to quench the steel is dependent upon the steel. For instance, A2 is an air-hardening steel, W1 is water hardening, and O1 is oil hardening. Then there are 10xx series, of which 1075 can be water hardened, but 1095 should be hardened in oil, and some people have had luck hardening 1084 in brine, but other have had 100% failure rates.

You don't use both oil and water, just one or the other, when quenching steel to harden it.

The specs for certain steel can be found on suppliers websites, and there are huge repositories of info on the internet at large. If you're serious about this, you've got some reading to do. This is a good starting point, but should be taken as gospel:
http://ajh-knives.com/metals.html

What does the color of the metal tell you? brown versus blue when heating?

I think this would be a great help for some people here. Sharing your experience is greatly appreciated too!

To harden steel, you have to get it glowing red/orange. This usually means about 1500 degrees F for simple carbon steels and some tool steels, and as much as 2100 degrees F for some stainless steels. This isn't easy to do without a forge, and it's nearly impossible to maintain soak times without one.

The colors of metal are an indicator of it's temperature. When tempering back a steel after hardening, you typically shoot for a straw color - barely visible coloration leaning toward a brass/bronze color. However, I don't trust my eyes enough to tell me, and I use thermocouple instead. And, keep in mind that color alone isn't the whole story. When tempering, it's a time + temperature thing. Some steels only need an hour, others need upwards of 3 tempering cycles of an hour each.

You can use color when grinding hardened steel to tell you when you've messed up. If your workpiece goes blue as you're grinding, chances are you softened it considerably (depending on steel). For that reason, I always have a bucket of water nearby when finishing a hardened piece of steel. I'm constantly dipping the workpiece in the water to keep it cool so that it doesn't discolor at all.

 

[leehljp]

Thanks for the information and the link. I can tell that timing as well as temp need to be very controlled. Nothing that I can do in a small home shop.

From what I remember of my dad - it was a guessing game at best. He certainly didn't keep metal (plow shears or other metals) heated that long. With an acetylene torch - Heat and beat, heat and beat to shape in as short a time as possible and finish with a dunking in water, but he did use a bucket of oil a few times - but for what, I don't have a clue.

 

[Wildman]

Doubt you can find good quality carbon turning tools today. They can cost more or about the same as low quality HSS turning tools. So price is also a major consideration. None of the major suppliers of turning tools offer carbon steel tools in their catalogs or on web-sites.

Mountain Heritage Crafters, LLC offers carbon steel turning tools by "Two-Cherries.

http://www.mhcrafters.com/servlet/The-TwoCherries-tools-cn-turning-tools/catogories

If link doesn't work check out prices at Http://www.mhcradters.com

Tools For Working Wood will special order Ashley Iles carbon steel tools for you.
http://www.toolsforworkingwood.com

Do carbon tool turning tools cut cleaner than HSS? Yes! Are they superior to M-2 HSS? Answer is both a yes & no. Today's M-2 HSS bowls gouges far superior to yesterday's carbon steel spindle gouge with reground bevel for bowl turning.

If you find a good quality used set at an estate sale/yard sale/flea market for a good price buy & use them. Unless you know the brand name stay away from those deals in a wooden box on E-Bay.

Once you learn to sharpen correctly you'll almost never blue your tools! It's not a good practice to blue your turning tools while sharpening regardless of the steel used to make them.

Cost and availability is the reason buy only M-2 HSS turning tools today.

JMHO, my new Kryo ½" round edge skew wasn't worth the extra cost. So not interested in paying more for ASP 2030 or ASP 2060 particle steels tools.

 

[pipecrafter]

Thanks for the information and the link. I can tell that timing as well as temp need to be very controlled. Nothing that I can do in a small home shop.

From what I remember of my dad - it was a guessing game at best. He certainly didn't keep metal (plow shears or other metals) heated that long. With an acetylene torch - Heat and beat, heat and beat to shape in as short a time as possible and finish with a dunking in water, but he did use a bucket of oil a few times - but for what, I don't have a clue.

Ah, that would be different. Sounds like he was forging the metal to shape. That's easy to do with torch to heat it up since you're not looking for a particular heat range (well, okay, you are, but there's some wiggle room) - but it's certainly the hard way.

 

[alexkuzn]

Hank,

I guess Kurt already answered your question for me.

In general I would advise against heat treating steel yourself unless you have kiln with electronically controlled temperature and know exactly what HT process recommended by manufacturer. Heat treating with torch will yield you less than optimal results.

 

[Wildman]

Many turners have made their own tools using a grinder or torch. It's easy to make a pyramid & round skew from HSS drill blanks with just a grinder. Lot of tool bit holders for hollowing tool are made by heating and bending out of various tool steel. Cutters or scrappers can be made by grinding profiles on inexpensive HSS steel & old planner blades, and inserting them into the tool handles you make.

Poor man's shogger, is a good example of home tools, which don't take much time or cost to make.

Not sure it's worth, money, and effort to get into worrying about heating & tempering steel given what's already available. If you want another hobby go for it.

Folks here might want to Google Jerry Glaser, and many of the innovations in steel he has brought to turning gouges, chisels & tool handles. Jerry Glaser sold that portion of his company to Cryo Steel Engineering back in 2005. Only place that carries Glaser turning tools that I know of is Highland Hardware. Check prices of Glaser tools might be an overkill for pen making. http://www.highlandwoodworking.com

A new comer and less expensive alternative is Thompson lathe tools, all A-11 steel, but you make or buy your own handles. If you make your own handles less expensive than Glaser tools. If you buy available commercial handles price bout same as Glaser gouges & chisels. He posted here trying to drum up business.

 

[pipecrafter]

Not sure it's worth, money, and effort to get into worrying about heating & tempering steel given what's already available. If you want another hobby go for it.

I don't know. If you're going to me making things from steel, especially if you're going to put them through the stresses of heating and beating or bending, then I think it's advantageous to understand a little of what's going on there at the molecular level. It could save your eye, hand, or face one day.

 

[amosfella]

You also have to know about annealing, how to undo packing from the hammer, stress relief, etc. A torch is very innefficient at heating steel, so I would recomend setting up a propane forge or an electric kiln, or even a coal/charcol/wood forge. They aren't that hard to make.
A book called 'The Art of Blacksmithing" by Alex Bealer would be a good place to start. Last time I saw it, it was about $10.

 

[Wildman]

Amosfella & Pipecrafter, your exactly right! Am too old to fool with steel!

Point of my previous posts carbon steel turning tools not that bad if they're quality tools. Also you can make a lot of simple turning tools without much knowledge, money or extra equipment.

Who hasn't made themselves a set of small hollowing tool from allen wrenches yet?

You can make your own pyramid or round skew in about an hour or less.

People have been making their own boring bars & curved hollowing tools from various types of steel before many of the commercial versions hit the market.

Several years ago, had a basic American froe, for splitting wood made at a local machinist/welding shop for $10.00. Made my own wood handle. Pretty sure the pipe and blade welded together simple carbon steel. Simple weld and grinding of the blade and in business. Works well! You can buy new froes already made for $50.00 plus.

If you want higher quality steel turning tools, both Glaser & Thompson got you covered.

 

[pipecrafter]

Point of my previous posts carbon steel turning tools not that bad if they're quality tools. Also you can make a lot of simple turning tools without much knowledge, money or extra equipment.

I agree completely! I built my first forge for less than $100 - which is less than a third the cost of a decent OA torch setup. The next one will be built for about $30 using leftovers from the first. Steel is cheap, and available from everywhere. Even the electric heat treat oven I'm working on will come out at slightly less than $100, and will get me all the way where I need to be with regards to heat treating even complex steels.

Knowledge, however, you can never have enough of. But, consider the source. I'm an information sponge, and like to fill my brains with seemingly unnecessary information.

 

[Daniel]

Me thinks there could be another side issue as complicated as Photography. Oh if we only knew what we where stepping into when we first eyed that pen kit. Actually I really appreciate this topic and hope to see some permanent articles and such develop from it. I realize that you cannot do it so much as a tutorial or get specific because each metal is different etc. I have wanted to make small parts for several years now. First was making my own penmill pilots from drill rod. I thought why not figure out how to harden it as well. not really a necessity but would be an improvment.

 

[leehljp]

Hank,

I guess Kurt already answered your question for me.

In general I would advise against heat treating steel yourself unless you have kiln with electronically controlled temperature and know exactly what HT process recommended by manufacturer. Heat treating with torch will yield you less than optimal results.

Kurt, Alex,

Thanks for your answers. I see the problem with my thinking here. My first experience in watching "heat treatment" was back in the stone age where as you guys are talking home shop high tech at the least. Totally different ball game. :wink:

Kinda of reminds me of a conversation I had last week with a young Japanese lady at church. Even though LOML and I have been knowing her for about 6 months and counseling her on her upcoming marriage, I didn't realize she was a programmer within a Toyota Motor company subsidiary. She named C and C++ or something else and asked me if I did programming. I said way back when - before she was born. She said, "Oh you know "Basic". I said "No, I was before that - I knew 'binary' at one time." :biggrin:


Back To Topic:
I think Daniel's suggestion is very good and is what I would like to see!

 

[amosfella]

I'll throw a bone to you guys. I can explain the general process of hardening. My grandpa learned blacksmithing when he was a kid, and as I lived on the same farmyard with him, he taught me some on the side. I'm far from knowing everything, but there seem to be some constants.
Before steel is hardened, it must be annealed. So, you heat the whole piece of steel up until a magnet will no longer stick to it, and you cover it in the fire, or you close the door of the kiln, propane forge, etc., and let it cool down over night. If you've been really cruel to it with the hammer, you might have to stress relieve it as well, which involves heating the steel to about 600-1000F and holding that heat for about 4-10 hours (depends on the intricacy of the piece, size, etc.).
Now that the steel is annealed, you can harden it. Here is where most people make mistakes. When hardening, you heat the WHOLE piece evenly till a magnet won't stick to it. Then you quench it, or harden it with an air blast, etc. (Learning how to do that on unknown steel requires some prior testing, and this assumes that you tested what you were working with.) when hardening, you can do it several ways. You can differentially harden it, which means that you make a mud paste (ashes, milk and flour is what some Japanese swordsmiths use) and coat the part that you want to be softer, and leave exposed what you want left harder. If you want to harden the whole thing equally, you'll want to temper it. Differential hardening doesn't always need tempering.
Tempering involves reducing the hardness to reduce the brittleness. There are many ways to do this. Before tempering, most will poilish at least one face of the steel. Some will temper by passing the object back and forth through the fire quickly until the right color is achieved. Others will heat a hard ceramic firebrick or plate of steel to red hot and laye the object on the plate until the correct color is achieved. Comes down to personal preferance. I find heating a plate more accurate. If you're forming a cutting edge, you want the edge to be hardest, while the spine or the back of the blade is softer. Doing a knife, you could hold the back onto the metal plate, and wait till it's a straw color starts to appear at the edge, or doing a lathe scraper, you could put all but the inch before the edge on the plate. Double edge knives are more complicated, but beyond the scope of this. Once the temper color you want has reached the edge, you can quench in warm water, and then polish or oil it to keep it from rusting. DON"T HEAT THE METAL WHILE POLISHING!!!!!!!!!!! Or you're back to hardening the steel again. This is most important with high carbon steel. HSS is less crutial, but should still be observed. Once the steel is polished, wipe it with wax, an oily rage, or a coat of teflon to keep it from rusting.
Handle your tool and enjoy. Take pride in your work, as you can now say that you made your own tools to make this object of art.

 

[pipecrafter]

As always, however, you really, really need to look at the steels you're using. Most steels must be tempered right away, otherwise you run the risk of allowing the martensite to continue to expand and put stresses into the steel - and before you know it, you've got cracks in the piece. That sickening *ping* is the sound of failure. I've been subjected to that more than once - mostly during my experiments with brine quenching.

And I disagree with some of this post. Normalizing (or stress relief) is a heat to just above critical temp (varies by steel) and allowing it to cool in still air to black. Annealing is when you raise the temp to above critical, and allow it to cool slowly over the course of several hours. The difference is very important because normalizing refines the grain size, allows the carbon and other alloys to more quickly enter solution, and makes for a much stronger steel after hardening and tempering. Annealing is simply making the steel soft, partly by creating huge grains of iron and other alloying elements.

When hardening, you need to follow the instructions from the steel manufacturer. For instance, 1084 is probably the easiest to heat treat. Bring it up to about 1500, and immediately quench in warm oil. O1, however, requires a short soak at 1500 before quenching. And other steels actually require being heated to well over 2000F before being quenched. The state of non-magnetic can occur as low as 1250F, and this is nowhere near hot enough to put all the alloying elements into solution and creating a uniformly hard piece.

Tempering also isn't just a color thing. For most steels it's a time PLUS temperature thing. The best results can be had from some steels by performing 3 tempering cycles at a temperature that will result in the hardness you need. For instance, I just finished a camp knife that's getting shipped on Monday, made from O1, and it was tempered for hour at 400 - three times. That will give it an edge that can be easily field-sharpened, as well as a very tough body that will resist chipping and snapping if used as a pry bar.

But, this is an incredibly complex subject. One that entire forums are dedicated to, not just one thread in a topic area. Like I said before, if folks are interested in heat treating steels for whatever reason, the best thing to start doing is reading - reading every piece of info that can be gotten. Hell, I've been researching and experimenting on this subject for two years or so at this point, and I *still* don't consider myself any sort of expert in the matter.

 

[Rifleman1776]

I live in Arkansas, a state with many expert knifemakers. We may have more of the best than any other state. The tradition started with Jim Bowie, or, at least, his reputation.
Enneyhow, as someone said, this discussion opened a bucket of worms. Nothing like when some knifemakers get together and start discussing (arguing) about the better method of knife making, stock removal or forging. The stock removal guys claim the steel as it comes from the foundry is as good as it is going to get and forging just messes up the molecular structure. The forging guys say you need heat and must pound on it to get the molecular structure lined up properly. Others say you must forge and layer (Damascus) the steel for best performance.
Where do I stand on this issue? Answer: far away. These guys have knives, usually very big and very sharp.