Moderators: Random Orbital Bob, nev, CHJ, Noel, Charley

 Reply
By CStanford
#972015
'Ball bearing steel' (En31, 535A99, or SAE52100 to the Americans) is quite close to being a 1% straight carbon steel. It has a little bit of chromium - about 1% to 1.5% - in it to help final hardness and depth of hardening, a tiny bit of silicon and a bit of manganese. It's been around for many years, and has, I gather, been used for edge tools from time to time. The fact that it's a simple alloy very close to 1% straight carbon steel may be part of the explaination for it's good edge-taking and holding compared to some of slightly more complex alloys; other alloys might do even better.

Basically Japanese 'blue steel.'

Check out the table found here (scroll down to approx. mid-page): http://www.astbearings.com/bearing-materials.html
Last edited by CStanford on 05 Jun 2015, 11:58, edited 1 time in total.
User avatar
By Graham Orm
#972017
Jacob wrote:
Graham Orm wrote:
Jacob wrote:Harder steel will keep an edge longer but is harder to sharpen. So it's a trade off.
Perhaps the logical best solution is the laminated blade - hard but thin edge steel on the face and a soft back for speedy sharpening.


the question Jacob is does good steel get sharper? It seems there is a reasoning that it does.
Depends on what you mean by "good steel".
I suppose hard steel must get sharper but I don't know. But that's not necessarily the same as good steel if it takes too long to sharpen.
You can get an incredibly sharp edge on glass but it'll only cut soft stuff (such as your skin) so that's no good either!

It comes down to compromises over the practicalities of actually using the tool on an actual job.

PS Stanley 8001 - did you mean Stanley 5001? These are harder than the blue handled ones, can be made very sharp, probably keep an edge longer, but take longer to sharpen.


Yes my mistake. Black handle yellow ring very early 5001's black handle white ring later 5001's with nickel finish. Blue handle 5002's (unknown quantity).
By Corneel
#972115
Toolsteel is a fascinating subject. I am far from an expert, just read a bunch of websites...

How a toolsteel behaves depends on at least two factors, hardness and chemical composition. How the steel was produced and with how much skill it was hardened and tempered plays a very important role too.

Rarely was a toolsteel designed especially for handtool woodworking. We want a very sharp edge and we also want it to be very easy to sharpen and hone too. Our demands on durability are laughable when you compare it to steels used in the industry. But those two important factors for us, compromise the durability. Durability comes in two forms, wear resistance and toughness. These contradict each other, a hard wearing toolsteel is usually less tough. Making the steel harder increases the wear resistance but decreases its toughness, it becomes brittle.

O1 is very simpe steel, it has about 1% carbon which makes it hardenable. It also contains a few other elements in small fractions which help it's hardening ability. W1, the more old fashioned tool steel, is even simpler, contains not much more then steel and carbon. It is not as easy to harden, likes to crack and warp. These steels have very fine grain and are easy to sharpen. They have a good compromise between sharpenability, wear resistance and toughness.

A2 contains about 1% carbon, 5% chrome, 1% molybdenum and up to 0.5% vanadium. The chromium, molybdenum and vanadium form carbides. These are very hard, much harder then the steel and carbon. But they tend to cluster together in much larger crystals when the steel starts to solidfy during manufacturing. These large crystals tend to create cracks in the steel. So while they increase the wear resistance, they are not so good for the toughness. They also make the steel harder to sharpen. D2 conatins even more chromium and vanadium making it even more wear resistance but less tough. In other words, better for plane irons then for chisels.

These are conventional toolsteels. They are mixed in a large furnace and then poored into ingots where they can solidify. After that they will be rolled flatter which compressed the steel too. The formation of the large carbides is a problem, especally vanadium is a problem. It is very good for increased wear resistance, but is also really likes to create very large crystals. Large fractions of vanadium are not possible in a conventional toolsteel. But the industry really wanted steels with more vanadium. That's why powdered steels were invented. The steel is melted, then atomised in a kind of spray. They cool very quickly so the crystals don't have the time to grow. Then the powder is compressed under very high pressure and heat to create a solid steel again. The result is a fine grained toolsteel. The steel makers can now add much larger quantities of vanadium. For example CPM-3V, CPM-10V, CPM-15V with increasing amounts of vanadium. That makes a very wear resistant tool steel which is still pretty tough. No magic here either, increasing wear resistance among the PM steels still reduces toughness. And while these steels are relatively easy to sharpen, they are still a lot harder to sharpen then O1.

Which brings us to sharpening technology. You need a sharpening medium comatible with the steel. While oilstones are perfect for O1 and W1, they are not so great for steel with a lot of carbides. You need something which abrades much more agressively, like modern waterstones or even diamonds.

Recently a "new" toolsteel was introduced by LV, PMV-11. They claim that it is a powdered toolsteel, has better wear resistance and toughness then O1 or A2 while it is still easy to sharpen. Of course they didn't invent it themselves, steel making is a separate industry. They most probably used one of the many special knife steels. There are plenty of these around. It is a stainless steel (easy to determine) and because it is still easy to sharpen it can't contain very much vandium. There are not many powdered steels with small quantities of vanadium. This steel still needs to prove itself in the handtool world. First reports are encouraging, but that was the case when A2 was introduced too.
By CStanford
#972125
Yep, people practically soiled themselves over A2 (and to some extent D2 and CPM process steel) and then the same crowd offered a repeat performance when PM-V11 came out. Any more "new" tool steels hit the woodworking tool market I'm going to buy stock in an adult diaper manufacturing company.

Good that you put "new" in quotes in your last paragraph.
By woodbrains
#972129
Hello,

Charles, have you ever used Hock A2 cryogenic plane irons or the Veritas PM V11? I strongly suspect if you had, your sniffy posts would stop. Both are truly remarkable steels and since steel like good old W1 is no longer made and O1 seldom if ever hammer forged to give it that good old grain structure, we need advances in steel technology if our craft is to prevail. I first bought an A2 plane iron after using a particularly ornery wood that actually curled the edge of my plane iron after a couple of passes. The hock iron did not falter. I recently tried a PM blade out of curiosity and it is even better. I don't understand the resistance to progress here. I particularly like the Clifton plane irons, but it looks like they will not continue making them. Tools cannot be hammer forged without tremendous expense, which most users will not bear, so arguing that old tool steel is best is moot since you will not pay for its continued manufacture.

Mike.
User avatar
By custard
#972130
Cheshirechappie wrote:
custard wrote:I don't normally join sharpening threads, but I would say that I've often noticed that the first few sharpenings of a new tool rarely bring it up to it's best. Furthermore, if I've nicked a chisel or plane iron and have to grind it right back then the same thing occurs, where it takes a couple of rounds of honing before the tool is again singing.

I wonder if the act of grinding an edge might have an adverse effect on the steel, and it requires some of the surface metal to be honed away (more than you'd normally remove in a single sharpening session) before it's optimised? Possibly some micro bluing that isn't actually visible to the naked eye (although I've experienced exactly the same thing from a cool running Tormek as well as a high speed grinder)?

This is conjecture, but if it's correct it would explain why you need to work with an edge tool for a while before discovering what it's really capable of (so all those "instant" reviews that get posted of new tools are especially useless). Furthermore it's another reason to avoid grinding right to the edge, and to try and preserve the edge by only grinding to within a mill or half a mill away from the actual cutting edge.


In industrial grinding practice, there is a phenomenon known as 'micro-cracking' which is a particular problem with harder materials (like hardened tool steels).

What happens is that the grinding generates very high temperatures very local to the action (we're talking microns here, not something you detect by keeping a finger near the tool edge whilst it's on the wheel). That causes the metal close to action to both expand (outwards), and soften, becoming slightly plastic - the bulk of the metal behind doesn't get enough heat for either to happen to any degree. The wheel passes, and the edge cools very fast, contracts, and loses it's plasticity, but can't entirely contract back to where it was because the bulk of metal behind it won't move to accomodate it. Consequently, tiny cracks form along the edge (or surface of a piece in a surface or cylindrical grinder). It's almost impossible to grind this damage away, because the localised heat applied by the grinding process just makes the same thing happen again.

In industrial practice, forced flood cooling is used to carry off the heat as it's generated (dipping in a can of water won't do!). In the woodworking situation, honing (far less heat) slowly abrades off the damaged bit. Thus, an edge straight from the grinder and honed once may seem brittle, but the brittleness disappears over three or four honings.

I'm not sure whether that's the only explanation, or whether other factors are involved, or even if it's completely irrelevant. It does seem to fit the symptoms, though.

From the practical point of view I think the practice of not quite grinding right to the edge should avoid the problem. Micro-cracking will still happen further up the bevel where it's ground, but it won't do any harm up there away from the cutting edge.


That's interesting, thanks for that.
By CStanford
#972136
woodbrains wrote:Hello,

Charles, have you ever used Hock A2 cryogenic plane irons or the Veritas PM V11? I strongly suspect if you had, your sniffy posts would stop. Both are truly remarkable steels and since steel like good old W1 is no longer made and O1 seldom if ever hammer forged to give it that good old grain structure, we need advances in steel technology if our craft is to prevail. I first bought an A2 plane iron after using a particularly ornery wood that actually curled the edge of my plane iron after a couple of passes. The hock iron did not falter. I recently tried a PM blade out of curiosity and it is even better. I don't understand the resistance to progress here. I particularly like the Clifton plane irons, but it looks like they will not continue making them. Tools cannot be hammer forged without tremendous expense, which most users will not bear, so arguing that old tool steel is best is moot since you will not pay for its continued manufacture.

Mike.


Well, I have a Hock iron in a Record 4 1/2 but alas it's O1. It's fine. It does stay sharper a little longer. It's harder steel, slightly more work to grind and slightly more work to hone. All in all it's about a wash, time-wise. Never have tried the frozen stuff.

I had a Lie Nielsen plane (a scrub plane) which of course came with A2 and I hated the cutter. I replaced the plane with a vintage Stanley. Love it. Love the plain high carbon steel, love the way it cuts, love the way it hones. I love it. It leaves nothing to be desired IMO. You can practically carve with that little pipper.

I demo'd a PM-VII chisel and while it was beautifully made I don't see what all the fuss is about. It's probably better as a plane iron. It totally did not rock my world.

So yep, I've used all these steels. I even had a mortise chisel in D2 which I loathed. I couldn't put an edge on that ba$tard with SiC sandpaper. Horrific. It never formed a wire edge just this little hump I kept chasing front to back that would never come off. Came dull and stayed dull.
By JohnPW
#972140
woodbrains wrote:Hello,

Charles, have you ever used Hock A2 cryogenic plane irons or the Veritas PM V11? I strongly suspect if you had, your sniffy posts would stop. Both are truly remarkable steels and since steel like good old W1 is no longer made and O1 seldom if ever hammer forged to give it that good old grain structure, we need advances in steel technology if our craft is to prevail. I first bought an A2 plane iron after using a particularly ornery wood that actually curled the edge of my plane iron after a couple of passes. The hock iron did not falter. I recently tried a PM blade out of curiosity and it is even better. I don't understand the resistance to progress here. I particularly like the Clifton plane irons, but it looks like they will not continue making them. Tools cannot be hammer forged without tremendous expense, which most users will not bear, so arguing that old tool steel is best is moot since you will not pay for its continued manufacture.

Mike.


There's a How It's Made video of chisels being hammer forged, and those were the very ordinary plastic handled socket type chisels. And Ashley Isles certainly hammer forge and I suspect others like Narex and Pfeil as well. I would guess whilst chisels with a bolster or socket are always hammer forged, the small American boutique makers have to makes chisels without a bolster because they cut the chisel from a solid bit of metal because, I've read on the forum, they don't have the equipment to hammer forge.
User avatar
By Derek Cohen (Perth, Oz)
#972157
Well, I have a Hock iron in a Record 4 1/2 but alas it's O1. It's fine. It does stay sharper a little longer. It's harder steel, slightly more work to grind and slightly more work to hone. All in all it's about a wash, time-wise. Never have tried the frozen stuff.

I had a Lie Nielsen plane (a scrub plane) which of course came with A2 and I hated the cutter. I replaced the plane with a vintage Stanley. Love it. Love the plain high carbon steel, love the way it cuts, love the way it hones. I love it. It leaves nothing to be desired IMO. You can practically carve with that little pipper.

I demo'd a PM-VII chisel and while it was beautifully made I don't see what all the fuss is about. It's probably better as a plane iron. It totally did not rock my world.

So yep, I've used all these steels. I even had a mortise chisel in D2 which I loathed. I couldn't put an edge on that ba$tard with SiC sandpaper. Horrific. It never formed a wire edge just this little hump I kept chasing front to back that would never come off. Came dull and stayed dull.


Yeah Charles, that makes you an expert on these steels! :lol:

Regards from Perth

Derek
By Corneel
#972159
In handtool use there is always the balance between long wearing and easy sharpening. Because we are no machines, we can't continue to work forever, so sharpening more often isn't as bad as it sounds. The pleasure of having a fresh edge is for some people more important then a longer lasting edge. It's very subjective of course.

D2 probably is a poor choice for handtools. It has too much chrome, is not very tough, is hard to sharpen. O1 is perfectly allright if you don't mind the shorter edgelife. A2 has a micro cracking problem, which can be dealt with a steeper bevel, it lasts a little longer then O1 but is a little harder to sharpen too. On PMV the jury is still out.

I don't know if hamer forging really makes a lot of difference for O1. I've never seen the Cliftons rising to the top in any of the many tool tests (amateur tests of course). The Japanese manage to make some remarkable stuff, they manage a great balance between the very hard cutting edge and the soft backing.
By rafezetter
#972161
Well up to the last few posts (steady boys - and you too Derek) this has been a fascinating read. I'm not surprised the Japanese seem to have the edge (sorry) on making super sharp, but also long lasting, tools. After all they started making swords hundreds of years before anyone else and to a standard that even relatively modern antique versions (the last 150-200 years or so) sometimes command 6 figures sums. For them the art is in the making, not the making of profit from that making, and it's worth noting there isn't a traditionally trained sushi chef in the world that would deign to use a western knife.

The info on microcracking and how to reduce it's manifestation is something I'll definitely try to remember as I've have to grind out a few nicks recently and have a load of old chisels that I bought I've not yet got around to sorting out. For the regrinds, I have (and would have continued) to just put them in my sharpening jig and sat it on a belt sander until the nicked edge was just gone.

It's also made me resolute to go over a few of my very new chisels, which have only been taken to my level of sharp edge (still paper slicing razor - or so I thought...) once or twice and hardly used, again. Prolly the reground plane blades too.

I'll be honest and say I've not noticed a difference, but then my sense for this sort of thing is still extremely new.

Someone might be able to answer a simple question though which may advance that sense... recently I was working some reclaimed cedar and in the box joint bases should a ChrVa tool steel chisel be sharp enough to slice out the endgrain instead of mostly tearing? (my sharpening regime finishes with 5000 grit wet,dry and a micro back bevel; good enough to slice paper).

If it should have sliced - what do ppl recommend to get that final zing for this sort of very soft wood as I have a fair bit of it to work.
By woodbrains
#972169
JohnPW wrote:
There's a How It's Made video of chisels being hammer forged, and those were the very ordinary plastic handled socket type chisels. And Ashley Isles certainly hammer forge and I suspect others like Narex and Pfeil as well. I would guess whilst chisels with a bolster or socket are always hammer forged, the small American boutique makers have to makes chisels without a bolster because they cut the chisel from a solid bit of metal because, I've read on the forum, they don't have the equipment to hammer forge.


Hello,

Drop forging is different. The only new tools available, forged by hammering, are Japanese tools, (blacksmith made) and only the more expensive of those (very!). The small grain structure, even alloyant distribution and even grain alignment found in tools produced by repeted heating and hammering. This yeilds steel with the best balance of toughness, hardness and fine sharpenabiliy. For example, the Stanley 5001 chisels (very good tools in the day) are made from a steel ( EN31, I believe) which is drop forged. The same steel could be used by Japanese blacksmiths, and hammered repeatedly and will be improved enough to enable it to be harder and tougher and take a finer edge, but exactly the same steel. (OK forge welded to a softer back too) For better or worse, metallurlogical developments try to impart these characteristics in steels without having to resort to expensive hot working the steels. There are always compromises though and some are more successful than others. But I do think cryogenically treating the steels does give noticeable benefits over what we have been used to in recent years and PM V11 is really good. On abrasive materials it is peerless for edge holding and can be got truly sharp, with my water stones. Can't say if it is easy on oilstones, I've not tried, though I suspect might take a while longer. The problem is, I suspect, there is such little interest in hand tool development over industrial cutting equipment, I don't suppose there is much effort put into the development of new steels specifically for planes and chisels, so steels will just be picked from stocks made for other purposes, to the closest approximations of what is needed. I think PM. V11 is a good approximation, though.

Mike.

Edit,

Clifton made fine plane irons by hammer forging, but seem to have abandoned the method in favour of cryogenically treated steel. I'd like to compare the results one day as their old irons were fine.
User avatar
By Jacob
#972173
Corneel wrote:In handtool use there is always the balance between long wearing and easy sharpening. Because we are no machines, we can't continue to work forever, so sharpening more often isn't as bad as it sounds. The pleasure of having a fresh edge is for some people more important then a longer lasting edge. It's very subjective of course.
.....

Well yes if you have a simple sharpening regime (freehand on one or two oilstones) it makes a nice little break and you have freshly sharpened edges a lot of the time. A bit like sharpening a pencil and about as difficult.
I think the obsessing about steel quality has a lot to do with the problems due to the pointless fashion for thick blades and complicated modern sharpening regimes.
User avatar
By Derek Cohen (Perth, Oz)
#972178
I am not a metallurgist, however I do have a fair amount of experience both using and testing aspects of the various steels in a woodworking context. There are a few accounts of these on my website (under Tool Reviews) for anyone with the interest. I have in use all of the time O1, A2, M2, M4, D2, CPM-3V, and PM-V11. My amateur experience ...

First and foremost, before one can make a pronouncement on any of these steels, it is important to get them sharp. This means using appropriate honing media. For some of these steels there is no free lunch. For example, when I first tried it, I thought CPM-3V just not capable of a sharp edge. I was using the wrong media. When I switched to diamond paste it came alive! Anyone here attempting to hone M4 or D2 with oilstones may as well be using a blunt nail for an edge. This is an extreme example, but just to get my point across. Now this is not a discussion of sharpening, the merits of various stones, or whether various steels are good or bad because they require something different. It is simply to point out that one cannot pronounce on a steel until you can get it sharp.

The second point I want to make is that all the steels have pros and cons, and you need to decide where your priority lies - some excel at ease of sharpening with simple media (such as an oilstone or a natural waterstone), but then struggle to hold an edge with anything more abrasive than pine. Some excel in abrasion resistance for planing, and others for impact resistance for chiseling.

I suspect that a key factor to edge durability is a combination of how fine the grain is, how hard the steel becomes, and how elastic it is. For planing, one may want more abrasion resistance (more chromium?) and for chopping one wants more impact resistance/elasticity. I'm surmising here - feel free to throw this out the window, but give evidence if you do so.

I have come across an interesting graph showing the correlation of these features ..

Image

This shows how the steels may increase their elasticity with chromium and moly.

Japanese laminated steels are essentially O1 steel but they do well, and I suspect that this is because the cutting layer is very hard and that this only survives as a result of a soft, elastic backing. They seem to do well both in edge holding when planing and when chopping in hard, abrasive woods (if my experience and tests count).

Steels such as D2, which have large carbide grains and many find hard to sharpen, appear to have more elasticity, and this be why they do so well in (Ray Iles) mortice chisels. I have a D2 blade in a jack plane, and it excels here as well. Perhaps like the RI, it is better at chopping. And yet high end planemaker Philip Marcou (in New Zealand) considers D2 a wonderful steel for smoothers. He argues that it needs to be left softer than most do.

O1 steel is really poor at edge retention when chopping end grain and planing abrasive face grain compared to all the steels above. A2 is about double its ability, and look where it stands in relation to other steels ...

Image

PMV-V11? I think that it is excellent for planing abrasive woods, but especially good for chopping with chisels. It would make a good alternative to D2 in mortice chisels, and runs close to laminated Japanese steels for paring chisels.

Regards from Perth

Derek