I’m a bit of an old chisel addict. I like to bring them back to life and see what they can do. I have Stanleys, Witherby’s, Swan, Pexto, Buck, Union, etc. All that is to say, I’m not what you’d call a wet behind the ears newbie when it comes to sharpening and using chisels. But one of my recent acquisitions has me frustrated and stumped. It’s a 1/2″ Swan paring chisel. The problem is that upon sharpening (using waterstones), in repeated attempts, it forms the biggest wire edge I’ve ever seen, and what’s worse, the wire edge has a sort of elastic tendency where it won’t separate cleanly. This steel behaves more like iron. Even when I have been able to coax an edge onto the blade, it deforms pretty much instantly upon being pressing into wood. My best guess is that somewhere along the line this chisel lost it’s temper. Does anyone have any thoughts on how I might bring back this steel to a reasonable hardness? As it is, this thing is destined for the recycler. Thanks.
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Replies
Samson,
You need to heat temper the steel, then anneal it. The process is iffy and you can fracture the steel as easily as harden it. But since the chisel is heading for the trash anyway, why not give it a try.
The "standard" way to harden is to bring the steel up to red hot with a torch, then quench it in oil (don't use water). Heat it slowly and evenly, with a broad flame. It will be hardened, but too brittle for use.
You can anneal it by placing it in a bed of glowing cooking charcoal and leave it there until the charcoal has died out (several hours to overnight. It should then have better characteristics than presently, but the art of hardening and annealing takes time to learn to do right.
Rich
Thanks, Rich. Any idea how the chisel could lose it's temper in the first place? Some of my best chisels are Swans.
That's really hard to say. It may have always been too soft and the previous owner got tired of losing the edge so often, and that's why you were able to buy it.
Of course, overheating a tool while grinding will take the temper out. Usually the steel shows the tell-tale "bluing" at the point of overheating. In that case, carefully grinding back to "good steel" is the thing to do. But the new grinding has to be done carefully to avoid the original problem, and the "good steel" is quite a bit further back than just the edge of the discoloration.
It's unlikely that the whole chisel edge could have been uniformly ruined by grinding overheating, but it's possible. In that case, careful grinding should take care of the problem.
Rich
If you quench the red hot steel in oil, be sure the oil is hot as well- too fast a quench rate will be more likely to distort or crack it . You might find a blacksmith who will do it and let you watch or there are books on the subject.
Yes.
Rich,
I think that there is some confusion with the terms here. The process you describe where you bring the tool to red heat and quench in oil is hardening (as you say). But annealing it is to bring it from the hardened state to its softest state to allow easy grinding etc. It is done by bringing to red heat and allowing to cool slowly.
But what's missing is tempering, where the tool is brought to a lower temperature after hardening to toughen the edge and make it less brittle.
I think in this case I would first anneal the tool, then rough grind it, or at least remove the sharp edge so it won't burn during hardening. Then harden it as described, but afterward, temper it by placing it in an oven at 350 degrees or so for an hour.
Depending on how hot the oven is you temper to a different hardness. Another way I've had some success is after hardening, polish the back of the chisel a bit and reheat with a torch about an inch back from the tip, watch as the colors move toward the tip. I forget the progression but when the straw color gets to to tip plunge in oil and cool it down then.
A blacksmith taught me how to do it with one heating, heat the tool (the first three inches or so) to red heat, plunge the last inch only, to harden it. Quickly stone the edge so you can see the colors, the residual heat in the shank that wasn't in the oil is enough to draw the temper to the tip, watch for the right color and quench.
I've never done this with an already finished chisel, only rough blanks so YMMV and all that. Be safe around fire and oil!!
Best Regards,
David C
Thanks everyone for all the answers and the links. I dunno if I'm up to smithery. I think I'll try to grind off a bunch and start fresh on the chance that at some point someone got overzealous on an electric grinder and softened the steel. I could see no blueing when I received the chisel before I began sharpening. Any ideas about how far back I would need to go if theis is indeed the problem - I mean are we talking about 1/8th inch or 1 inch or what? Thanks again.
"Any ideas about how far back I would need to go if theis is indeed the problem - I mean are we talking about 1/8th inch or 1 inch or what?"Take a small file and lightly run it over the end of the chisel (do it on the bevel side, not the back). If the metal is soft the file will 'bite' into the surface. If it's hard the file will 'skate' over the surface. Move up the chisel and see where/if it gets hard. That will tell you how much is soft and then you'll know whether to grind or re-harden the chisel.If it's too soft you got two ways to look at it. The first is that it's no good and you have nothing to loose by trying to harden it yourself. The second is that you don't want to take the chance of ruining it, so find someone that knows how to temper it. Here is a link to the Artist-Blacksmith's Association of North America. Maybe they can help. (If they weren't already mentioned.)http://www.abana.org/
Thanks for the file test trick tip. It shows this chisel to be very soft at the business end, and not much harder even much further back. So now I need to consider what to do next. Thanks again.
David, Thanks. I believe I was describing tempering in the process I called mistakenly called annealing. Your tip about annealing, then grinding is good, but I think that would be most useful for a tool that had no bevel to begin with. Rich "I used to know all this stuff."
The annealing process that works well for me is to heat the steel to dull cherry then plunge the piece in a bucket of dry sand and let it set for a couple of hours.Work Safe, Count to 10 when your done for the day !!
Bruce S.
Samson
Rich has got you going in the right direction. In my other business, I do quite a bit of metal fabrication. I'm no metallurgist, but I seem to remember back in one of the area's of the brain not yet destroyed by ale that once you quench the chisel, the annealing process is all about the time and temperature combined. It has to be kept at a certain temperature for a certain amount of time. I don't recall what the numbers are, but perhaps a google, or a good metallurgy book can help. I know of a few guys who have made chisels out of files, and have used their ovens set at a certain constant temperature to achieve the final hardness desired.
Perhaps Adam will jump in here. I seem to remember him talking about this earlier in the year.
HEY ADAM, chime in here!
Good luck, and let us know how it turns out.
Jeff
Samson,
To add to what Rich and Jeff have suggested: I can't find it right now, but there was something I reading in the past couple of weeks that suggested putting your piece of metal to be treated in the oven (after the cherry red heating and oil quenching -- make sure you get all the oil off or SWMBO is gonna be real unhappy about what you're about to do to her oven....) heated to IIRC about 425° F for about an hour or so (you need an accurate thermometer for this, not the one supplied with your oven). That temp and time is supposed to result in the steel being heated to the "straw" color that is about right for getting a hardness of Rc 58 to 62. I have never tried this, so I can't attest to its accuracy.
These sites have some ideas that you might be able to use:
http://www.primitiveways.com/pt-knives-1.html
http://www.cs.cmu.edu/~alf/en/hocksteel.txt
http://www.norsewoodsmith.com/oldtools/sn-screw2/rivet2.htm
http://www.norsewoodsmith.com/oldtools/awl/awl.htm
http://www.rexmill.com/ (click on "Heat Treating" on the upper right; also has some links to other sites with heat treating info)
Hope that this is of some use to you.
Beste Wünschen auf ein glückliches und wohlbehaltenes Neues Jahr!
Tschüß!
Mit freundlichen holzbearbeitungischen Grüßen aus dem Land der Rio Grande!!
James
Samson,
James has given you some good links, there is lots of info on the web. People here are mixing up their annealing and tempering a bit, but the links should describe the process. You anneal a piece of carbon steel to soften it (prior to shaping it), harden it by heating and quenching in oil (to make it hard like a file), and then temper it (which takes out the brittleness, but not as soft as the annealing process). The quenching is usually done in oil (motor oil, cooking oil, whatever) and the tempering can be done with a torch or an oven. This process is for "oil hardening" steel, such as O1. There are many other types that are air hardened, etc. You will likely have to just guess which it is, but I would try the oil process. I have made a lot of knives (and a few chisels) for O1 steel and liked the results.Woody
I'm not familier with swan chisels, but I do know that in the old days, very often a piece of carbon steel would be welded to a piece of softer steel to make a chisel. This was done because carbon steel was expensive and hard to make. If swan chisels were made this way, you may have one that has been ground down past the carbon steel, leaveing only the soft steel. If so you are hooped. If not, you need to heat it to bright red hot, quench in water quickly to harden it, and then reheat to red hot and quench in oil when the edge has cooled to straw color. You should file the edge after you heat it so you have fresh steel to watch for color change.
I have an old "The James Swan Co." 1/4 mortiser and it sharpens very well and holds as edge as well. One of my favorites. Does not appear to be a bimetal chisel at all. I believe your suspicions of temper loss may be correct.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
I was reading about how someone treats his plane irons and they're O1 steel (oil quenched, 1% carbon) and the instructions from McMaster-Carr said to heat it to just past cherry red (just into orange) and make sure it won't attract a magnet, quench it and put it in a 350 degree oven for about an hour. Let it cool and it should be in the R-60 range.
Obviously, remove the handle first.
Samson,
Here's what you need to do:
Heat the middle of the shank of that chisel until the tip (that you aren't touching with the torch) gets to about 1500F. You probably won't see any colors. Since your Swan is undoubtedly W-1, the magnet trick may not work. All carbon steels go non-magnetic at 1350F or so. For .77% C steels, that's the critical point. For steels with more or less carbon, the critical temperatures are increasingly higher as you move away from .77%. You can safely assume you are dealing with at least 1095, or .95% C (carbon). So how will you know when you are there? That's the trick of it. Some guys just go for it, some know by experience. I use a tempilstik. You can get these at welding supply stores or online through the big industrial suppliers.
W-1 is water quenched. You can quench in oil, but you may get some pearlite which will weaken your edge.
Theorhetically, if it didn't work, you could just do it over again. But there's this thing called decarburization where the oxygen in the fire (I hope i have this right) bonds with the carbon in the steel and takes it away- leaving you will a lousier tool. So this really is something you only want to do once if possible.
Annealing by eye is possible, but I can't do it. So temper in a 350F oven for 30 minutes. I think there's some advantage in doing this soon after quenching.
I have a good book- called something like "tool making for woodworkers" I think the author is Ray Larson or Larsen. Larson may be the cartoonist.
Adam
PS- to answer your other question- that chisel have have had its temper drawn by over ambitious grinding, or it could have been in a fire, or it could be just a dud. Making chisels and chisel steel is fairly complex. Accidents can happen,
Edited 12/29/2006 10:34 pm ET by AdamCherubini
Hi AdamAll carbon steels go non-magnetic at 1350F or so.[The curie temperature, at which the low temp phase in steel turns non magnetic, is 1420F approx (770C.)] Most of the low temperature phase disappears at approx 1330F (723C) give or take 20F (depending upon the alloying elements,) so most of the magnetic properties in a tool steel disappear at this lower temperature.Soaking temp for a eutectoid (0.8%C approx, you've used 0.77 which is one of the quoted values) is 20C above the transformation temp, making the soak temp the approx 1360F you've quoted.You can safely assume you are dealing with at least 1095, or .95% C (carbon). W-1 is water quenched. You can quench in oil, but you may get some pearlite which will weaken your edge.Also correct - if you have pearlite (not the hard phase in steel required to make an edge,) then you can safely assume that the centre of the blade is also unsuitable.But there's this thing called decarburization where the oxygen in the fire (I hope i have this right you do) bonds with the carbon in the steel and takes it away- leaving you will a lousier tool. So this really is something you only want to do once if possible.Completely correct. If you have fresh air getting to the blade or if the flame has a surplus of oxygen (not a reducing flame) then you can easily strip the carbon from the surface. It burns out of the steel in the same way that it burns out of a log in a fire, from the surface layer, reacting with oxygen to form Carbon Monoxide. At air temperatures below about 770C (a LPG flame is approx 1400-1600C), then the carbon monoxide further burns to form Carbon Dioxide.Annealing by eye is possible, but I can't do it. So temper in a 350F oven for 30 minutes. (this works fine, but I've found that it's about 340F (170C) x 90 minutes for O1) I think there's some advantage in doing this soon after quenching.[it relieves the stresses before they have a chance to build up and break something. There's also an advantage in waiting as more retained austenite (soft, high temperature) may transform to the martensite (the hard phase you need to make a blade.)]Cheers,eddieEdited 1/4/2007 5:54 pm by eddiefromAustralia Further edit after you read this but before post 64 appeared.I wrote this after I read post 15 but before I read from post 16 on and saw the controversy that ensued.
Edited 1/4/2007 6:34 pm by eddiefromAustralia
Further edit to put all the html tags back in - I use Firefox and not Internet Explorer, so this is the only way I can emphasise things
Edited 1/4/2007 6:56 pm by eddiefromAustralia
and still cleaning up the HTML tags
Edited 1/4/2007 7:00 pm by eddiefromAustralia
Samson,
My advise is to ignore the advise you've gotten here. The Internet provides access to a lot of information and a lot of that simply isn't reliable. This thread is a good example. There's just too much wrong with much of the information here for any of it to be of use to you.
The quickest way to damage tool steel in heat treating is to overheat it. I fear, if you follow the advise here, that's exactly where you're going to end up. There's not a bit of advise on how to avoid burning the steel here and I don't think you'll find it on the web--I haven't and I've spent years looking for it.
A good example is that you've been told your chisel is "undoubtedly W-1." Maybe so, but I don't have that poster's crystal ball. James Swan & Co was in business from 1877 to 1951. Oil hardening steel was in common industrial use well before 1951 as were a lot of other more exotic alloyed tool steels. I'm not even sure when AISI started classifying steel with the W, O, A, D and other designations. Thankfully, David got the nomenclature right but he seems the only one.
I'd try to explain how to re-harden your chisel but, at this point, my effort would only get lost in the noise. I now know a dependable technique but I've never tried it on water hardening steel. I'll spend the day getting information you may find helpful posted on our web site. I don't have the time, but I've been planning on getting it up for weeks. I'll send a private message when it's up.
Oh BTW, years ago I did re-harden a Swan chisel. I'm pleased with the results and I use that 2" chisel often. I quenched it in oil. I don't know how many plane irons and other tools we've made and heat treated but the number would be in the thousands.
Thanks for setting us ignorant types all straight, Obiwon!
J
Larry, absolutely spot on. Advice based on speculation, no matter how well intentioned it may be , can lead to grief: as you said , nobody even knows what type of steel it actually is ....
We look forward to seeing the information you mention on your web site.
Samson- if it were me I would find a competent black smith or a shop that specialises in steel hardening, if you are keen on the chisel.Philip Marcou
Well, I would follow Larry's advice. Adam's advice of temperstik [SP?] stuff is what I would use if I needed to shoot for a certain tempreture. I've used it and it works good.
However, even at that the result will not be certain. My feeling is, arm yourself with the procedure you can follow and trust. Try it. If it doesn't turn out as expected, try again. The worse case is the chisel will be unusable--sort of just like it presently is.
Take care, Mike
All,
Well everyone else has jumped in here, so I will too.
Fellow named Alexander Weygers wrote a little book called I think, Making Your Own Tools", that gives some good basic blacksmithing information. Written I think back in the hippie days, it is all about recycling scrap steel into useful homemade tools, and gives suggestions on how to identify the various types that are out there. Also directions on hardening and heat treating, annealing, as well as forging techniques (and making a forge). If you are at all interested in steel and its properties, it is a good read, even if you don't intend to do any forging. As others have pointed out, there is more to the subject than can easily be addressed in a short note. For instance, the colors you are looking for in tempering, are entirely a different thing than the colors you go by in forging/hardening....
A note: when the steel is at white heat, and you see it start to melt and throw off spangly little sparks, it's a pretty good bet you've burned it-damhikt.
Ray Pine
Well, IWilliams, You have certainly set all us dummies straight. Sorry that your words of wisdom (which you have not blessed us with) would just get lost in the "noise" here. Let me remind you, as the first to respond to this question, that I said my advice could just as easily result in turning the tool to junk as helping. But that since the original poster said he was going to throw it away anyway, he had nothing to lose. What better way to learn than by working on disposable material? Sure a complete instruction session in metalurgy would have been better, but that's not the point of the request. And heating a chisel to red hot does not get it near the point you warn will happen.
Edited 12/30/2006 5:57 pm ET by Rich14
"...And heating a chisel to red hot does not get it near the point you warn will happen."
I disagree. In fact, I've had the unfortunate experience of burning steel and it's incredibly easy to do.
Here's a rough draft of what will appear on our web site. I've worked on this almost steadily since my last post. Neither of my partners have seen it so it may come down in a hurry. I've been carrying a 1450º Templestik in my shirt pocket for weeks as a reminder to finish this particular web page. I've had it up for a few minutes and I can think of several things that need to be added. The link is HERE.
rather blurry-eyed and even more grumpy
Larry Williams
The method I described is the method I use to harden and temper tool steel, it works. You may know of a dependable technique, but have never used it, whereas I know of dependable technique, and have used it.
Folks,
Now don't take Larry the wrong way! He does get a might grumpy at times, but he does know of what he speaks. I'd just as soon be told the truth straight-out and unvarnished as get a bunch of flowery nonsense...but that's me.
I have a several C & W tools and the steel holds a keen edge, no doubt about it. So might as well take notes.
Thanks for posting the info on the website Larry, let me know when it's there, please.
I will mention, in defense of my earlier advice- that the other option beyond experimenting with rehardening and tempering the antique chisel was to discard it. So there wasn't too much risk in failing.
Best Regards to all for a happy healthy and prosperous new year!
David C.
Now don't take Larry the wrong way! He does get a might grumpy at times, but he does know of what he speaks.
QFT!
Telling Larry he doesn't know how to harden/temper or sharpen something is like telling Maloof he doesn't know how to build a rocker...
Hah. Think I'll go back to hiding...
Mike
I think Adam is pretty close to the mark. I hang out with a blacksmith buddy. We make knives and tool in his shop. Forging the piece is easier then heat treating it- which is very tricky.
Not knowing what sort of steel you have it will be very difficult to do this correctly. I doubt you will get it exaclty right. Also the tool is thinner at the edge and thicker in the haft and will heat differently and cool differently.
I'd heat it as evenly you can with a charcoal fire or torch. The difference between an oxidizing/reducing flames is more important if you are trying to forge weld. You needen't heat the thing until you get scale on it.
Let it get hot (straw/ light blue) and then quench it in water. When cool put it in a toaster oven at about 325 for two hours. Then bring the heat down about 50 degrees an hour and let it cool in the oven. That aught to leave it pretty hard but not unsharpenable or overly brittle. You will probably have to regrind and hone it.
You probably can find a blade fabrication shop that will heat treat it for a nominal price.
There is alot of science to this that I don't understand. I think the above will work well enough. The best chisles in my shop were hand made by an old cabinet maker out of old planer blade steel. I'm sure he wasn't much more scientific about it.
Good luck.
Frank
Edited 1/1/2007 10:45 pm ET by Biscardi
Samson. after reading most of the posts . I find many posters using the word annealing, in place of tempering
If the steel in that Swan won't keep an edge, it probably side stepped the heat treating process.
A simple test for you is to try to file it with a single cut mill file. Just give it two strokes of the file. If you can easily remove material, it is dead soft (annealed) If the file skips across as if made of glass, it's hardened. (almost brittle)also it will 'glaze' the file and leave a shiny spot where the file failed to cut into the steel.
Tempering is the process last used in heat treating to reduce the ultra hard steel(brittle) back to a hard but tough condition.
The mistake many make when hardening and tempering, is to heat the whole chisel and dunk (Quench)it abruptly in cold water or oil. The first inch or so should be heated cherry red at the start and work the flame rearward and increasing the speed and lift the tool smartly away from the tool at the areas one inch point The trick is not to create a sharp delineation
where hardness abruptly meets softness.The blade will have a tendency to snap in two at that point. Some cheap chisels are only 'case hardened) That is, the hardness is only skin deep through out blade and once the tip is sharpened a few times the softer material only remains... Usually case hardened steel is not capable of being properly hardened. Steinmetz.
Edited 12/30/2006 10:58 pm ET by Steinmetz
After a day with the computer screen yesterday, I spent some time editing and fixing the information in the link. I hope it's proves of value to those who have an interest in small-scale heat treating.
I think you've got some bad information or half a story from somewhere. Decalescence is not the same as critical for all alloys except .77% C. Its not that hard to understand the basics, but it helps if you are looking at a phase diagram for this: The phase change begins for all steels at 1335F. That change causes all steels to go non-magnetic. That's also the point at which decalescence begins. My understanding of decalescence is that the heat energy ceases to make the steel proportionally hotter and instead is transferred to effecting the phase changes. Above 1335, the diagram looks like a shallow Y centered on .77%. Alloys with more or less carbon form cementite or ferrites (I'm doing this from memory), but the formation of austenite, the point at which all carbon is absorbed into the crystals, is above the Y.Old W-1 is often very high in carbon- sometimes as much as or more than 1%. So the critical temperature may be close to 1500F. Note that this is 150F over the point at which it lost magnetism. There's absolutely nothing wrong with heating above that. Its important that the core temperature be 1450 or 1500, so a 1500 or even a 1600 tempilstik isn't a bad idea. I must admit that I'm a bit surprised to see this same sort of misinformation on many blacksmith/bladesmith websites. Even Ron Hock has this wrong. Tho Hock does mention decarburization that I talked about earlier. I'm interested in how you deal with that. Do you surface grind after heat treating? How much do you take off? The layer could be as much as .020" depending on the amount of oxygen in the fire. Coal fires are the worst for this. Depending on how much you surface grind, your customers might enjoy learning that their blades will get better with repeated honings!Happy New Year!Adam
Okay Adam, I'm still waiting to hear from a couple of the people who've been helping me with this and I'll change or add what they suggest. None have had a problem with my use of the term "decalescence."
In response I can start with the following from the 1943 edition of Machinery's Handbook:
View Image
In an inert gas atmosphere furnace one can do a lot of things. The purpose of the information I'm trying to provide here is to enable people to get the most from the steel they're trying to heat treat while avoiding a lot of esoteric metallurgy information and to be able to have success with minimal equipment. If people will do as I suggest, they'll be able to do just that. It does work.
The beauty of the system is that it results in a pretty complete conversion of the ferrite/pearlite to its austenitic phase. The person treating the steel doesn't have to worry about color or temperature. Using the appearance of flux on the surface as a guide eliminates all that. Yes, the higher the carbon content of the tool steel, the higher the critical temperature. The conversion to austenite is still the same process as is the appearance of the flux. It does this while limiting decarburization to the surface and keeping the grain size of the steel fine. In an oxygen atmosphere, the longer the steel is at critical temperature the more decarburization and the coarser the grain. This grain size and decarburization increase also happens with temperature increase above the critical point. Surface pitting is the result of decarburization below the surface and this method limits or eliminates that.
You can nibble around the edges of this all you want, Adam. We've invested a lot of time in working this out for our own use and that of others who share our interests. It works and works very well.
If you're interested in helping figure out the chemical composition of the flux, I'm up for further discussion. I think it's a form of iron oxide, Fe2O3 or Fe3O4, forced out of the shrunken austenitic matrix when the unstable (at critical temperature) Fe3C gives up its carbon to form CO or CO2. A PhD metallurgist and a PhD physicist I've been talking to aren't sure about that.
My understanding of decalescence is that it indicates the phase change. Again, for .77%C steel, the tip of the funnel decalescence point would accurately indicate the change. For every other alloy it wouldn't. I could be wrong, but that's my understanding. Regardless, the term is misleading and pointless. We're not measuring a drop in temperature rise. What we are talking about is a phase change- Even more simpler- its the absorption of C into the iron molecule. Anneal it/slow cool and all the C works itself out again. Quench and you can "lock in" the carbon.BTW, We've come a long way snce the 1940's- whenever I hear folks confusing magnetism and critical points I get suspicious. And its needless to even discuss this sort of thing in this forum- I can kinda see where you are heading and I have a couple suggestions:
1) Skip the science. Respectfully, you're not going to get it right- its very complicated- way too complicated for woodworkers, who probably aren't all that interested in metallurgy. We're still learning some of this. The guys I know don't all agree on it. There's what we learn in school and what actually happens at the mill.2) Tell us how YOU do it. Don't tell us what you think is happening, because again, you're probably going to be wrong- and this is no indightment. There are alot of blacksmiths using the magnetic trick and getting good edges on their high carbon steel. 3) I don't agree that your methods are good for us. Industrial heat treaters don't want to spend the time or energy to heat steel above its Tcrit. But we don't care. I say forget the flux and colors and just use a tempilstik 100-500F over what you think you need. Its non-subjective, and costs $20. Otherwise, since many of us can't accurately id our alloys, just get the 1500F tempilstik (and I'm spelling that correctly for you googlers) and forget it. And you Larry, could really do the same thing. At 1500F, you're over 1000 degrees F away from burning your steel. I don't know what you're talking about with that issue.4) If you really want to help us: a) debunk the magnetic trick as I have described- post a copy of the phase diagram
maybe.b) tell us about decarburization and what you do about itc) tell us how to hold the MAPP cylinder and where to point the flame! See, that's the stuff you know and we don't.d) how to build a mini forge/kiln out of cinder blocks and fire brick (and then where to hold the flame)e) and lastly, explain quenching. I've heard from guys who concern themselves with cavitation. Does it really matter what you quench with? See the text books say you WILL get pearlite if you quench W-1 in oil. But does it really matter? Do we always get pearlite anyway?Not that you deserve my respect with your insulting posts, but respectfully, I think your time and effort are better suited interpretting this for us and providing a stepped up no nonsense version of Hock's or Dunbar's home heat treating for dummies. As a side benefit, explaining your process step by step would be of interest, tho not necessarily use.And BTW, don't call us names. Also- for all of you- guys who mistake tempering and annealing aren't dummies. Both processes are similar, they both soften the steel by coaxing carbon out. Its an intuitive understanding. There's a disrespectful tone on Knots that I really don't care for. Had FWW been more heavy handed earlier this could have been a much better forum, imho.Adam
Edited 1/1/2007 2:40 pm ET by AdamCherubini
Adam, are you saying that Larry's "flux" method of determining when the proper temperture has been reached won't work or only works for certain alloys?
"Are you saying that Larry's "flux" method of determining when the proper temperture has been reached won't work or only works for certain alloys?"No. I don't know anything about the flux except what Larry wrote. I have no idea what's causing the flux. I'm saying the magnet method only works for certain alloys. I'm also saying decalescence may be related to the magnet in that it indicates a phase change, but maybe not the right one.I'm not sure why Larry is interested in the flux, but whatever. Its interesting. I don't agree that its a practical method for a woodworker. For me, the most practical bomb proof method of determining phase change is a 1500F or 1600F tempilstik. If you want to work HSS turning tools, get the 1600 and use it for all of your heat treating. If you don't work HSS, get the 1500.Adam
My understanding from reading Larry's webpage is that he regards using the appearance of the flux as the best visual method for determing when the appropriate temperature has been reached.
I assume that if a temp crayon is used then some visual method is used to determine when to pull the metal out of the heat and check it for temperature. Perhaps the appearance of the flux would work for that.
Larry only mentions the magnet method once, and doesn't recommend it. Instead he advocates the fulx method.
Dear Adam,
I read this thread over twice, and don't see where anyone resorted to name calling. It is interesting that you don't mind lecturing Mr Williams on the fine points and nomenclature of metallurgy, but bridle at his attempt to differentiate between something as basic as annealing vs. tempering.
I see nothing "intuitive" in the difference between reducing a metal (steel, brass, copper) to its softest possible state (annealing) and softening steel only to a degree (tempering) to achieve a desired working quality for a tool's particular use. The use of temperature crayons or watching for colors to run down are just to remove guesswork or intuition.
In my own experience, I've found that experience and know-how trumps theory and book learning in the arena where sweat is shed, and hands are getting dirty.
Best regards,
Ray Pine
Ray,I guess I just don't care for Larry William's conversational style. The bluster of ignore everyone, everyone's wrong then laying some dubious baloney on us. That bluff needs to be called and I'm calling it.I don't think its wise to shy away from academia, or disrespect it. As an engineer, I see all too often where practice and theory diverge tho. In my case, on this subject, I've actually got both in my back pocket (which didn't help): As you've probably guessed, I've got a couple engineering degrees and an interest in early tools. So I've read the text books and the hippy blacksmith stuff and tried it myself. I built myself a mini gas forge. In my experience, I couldn't see the colors- I never saw the colors and I sure as heck didn't see anything that looked flux. That doesn't mean it didn't happen. The critical point isn't close to "cherry red", it comes and goes without fanfair. I tried the magnet trick- you asked about the actual doing, right? - there I was with these welder's gloves on, which have fingers long enough for a midget, so they're like oven mitts, and I have tongs in either hand, and I have this magnet and everything is metal, its sticking to the post vise, its on the forge, its stuck to the anvil, and now the workpiece is cold. I mean, the colors and flux THAT'S the theorhetical part. I'm talking about the real world- Bottom line- (and this is what I've said all along) I can explain some of the metallurgy, but I always recommend skipping the metallurgical mumbo jumbo, and the hippy blacksmith hokum and get a tempilsitk. Adam
Edited 1/1/2007 10:04 pm ET by AdamCherubini
I only could find one instance of Larry mentioning the magnet method, and he wasn't recommending it.
I also didn't see Larry "shying away from" or "disrespecting" academia. In fact it sounds like he's discussed this with various academics and others well versed in metallurgy.
Larry presented what works for him based on his experience, the flux method. Just because you found a different method which you prefer does not mean either of you are wrong. There can be more than one method which works.
Bluffing? Bluffing? Who's bluffing? I've got this comical metallurgist's costume I don on weekends and go pretend to be one for the public. I've got the patter down pat. It makes me a regular g*dd*mn expert, don'tcha know.In an oxygen atmosphere, over heating the steel burns the carbon out of it and can do that to well below the surface. That's what I'm telling people how to avoid. With your slap-dash method it's no wonder you accept deep decarburization as inevitable. Every time you heat tool steel there's a risk. With the Tempilstik, you work with a minimum temperature but no maximum. Can I advise you to stay out of the credit card business? If you thought someone was risky , you'd issue them a card with a high minimum credit limit but no maximum.I don't really care if people heat treat, let alone how they do it. If they decide heat treat steel, they're welcome to follow what ever advise they choose. I know how I avoid turning good tool steel to low carbon scrap, it works and is very "real world".
Larry, Honestly, I object to your statement that I and every other poster should be ignored. That's fundamentally not what internet forums are or should be about and I think you owe us all an apology. That aside: You have some very fundamental flaws on your webpage.
You obviously have no idea what decalescence is or where it occurs. Ditto for the loss in magnetism. As both of these are supposed to be harbingers for the phase change to austenite, these aren't minor, "nibbling at the fringe" issues as you put it. This is the very heart of heat treating, the most critical step for production or home heat treaters.Beyond that, in my mind the most interesting of your musings, don't appear on your webpage: Decarburization, and crystal/grain growth. I'd like to learn how you deal with both. You've hinted that you try to control max temp to prevent grain growth. Did you know that you can reduce crystal size by cold working? Have you tried this? I would think a complex molding plane blade could benefit especially from this treatment.All said, I stand behind my recommendations. I think you're missing the point that the MAPP torch is incapable of overheating the steel. It probably took me 5 minutes to get to critical. I just don't think there's enough heat in that torch to overheat (or decarb) a chisel held in a machinist's vise.One more thing for everyone else- my interest in this subject extends beyond the miscellaneous repair of an ancient chisel. What if you could take nice looking but flawed chisels- say new Sorbys, and make them into absolute killers that would put japanese chisels to shame for under $50 (not including the chisels)? That's the subtext of this discussion. Its technically possible and not that difficult to pull off.Adam
Adam,The Internet gives access to all kinds of information. On one hand, it can be the kind of information Sampson was getting on how to heat treat his chisel. Following a lot of what appears in this thread, he would have as much success as if he'd been told to cut delicate Edwardian dovetails with a splitting maul. With a little work and patience, the Internet can give you access to some of the foremost experts in the World on any subject. I'm a little blown away by the help I've been able to get with my little web article. It's still being looked at and the article is far from done. Last night I got an e-mail from one of those metallurgy experts suggesting I change one word. That's been done. My first advise for your effort at working on new chisels is to dump the MAPP torch. A MAPP torch just concentrates too much heat in too small an area.on edit:Oh BTW, it wasn't me who insinuated woodworkers aren't smart enough to grasp basic understanding of heat treating. Or maybe it was just an insult aimed at me? More of that "disrespect" you were whining about earlier?
Edited 1/4/2007 9:36 am by lwilliams
Alright ladies. Let's not turn this into a festool vs. ez argument. Plenty was learned here. It was a good thread. Let's burn down the trebuchet's with either torch and get back to sawdust.
Jeff
So Samson, after the loads of useful? advice you have recieved, what is the outcome of your Swan?
I'm scared to touch it. ;-)
I doubt I'll be so brave as to try to heat it and quench it and temp stick and bake and ...
I'll likely give it to someone who has some smithing experience and knowledge to have at it. I got the chisel in a group I purchased which had a Union of the same width. The union sharpened up a treat, so I have no pressing need for the Swan.
Oh, go ahead!
Go for the gusto! Life's short.
Rich
Yeah, and might well be much shorter if I start messing with torches and shoving glowing steel into oil! ;-)
Nah. Piece of cake!
I would speculate that one reason your chisel might be quite soft is that it might have been hardened (and tempered) primarily in the last 1", the rest being left softer to make it tougher. After many years, the hardened part may have been ground away.As far as the art and/or science of heat treating goes, I suspect that consistency is what more knowledge can get you. A little uncontrolled messing about could in the unlikely best case lead to results comparable to those obtained with professional equipment and expertise. In the worst case, you could totally destroy the tool (and burn down your neighborhood.) From what I've read, it seems fairly likely that you can learn to improve the tool so that it will work satisfactorily, though probably not as well as it could. If you can have fun giving it a try, why not? In this case, an unstated objection appears to be that a Swan chisel is of sufficient worth that it should not be sacrificed for such a purpose.
Alan,
"In the worst case, you could totally destroy the tool (and burn down your neighborhood.) "
All right!
Rich
Samson
I've got a fantastic idea. With a bimetal blade in the bandsaw, resaw the chisel in two. Let's send 1/2 of it to Adam, and the other half to Larry. Let's see who can actually get it to the correct hardness/decalesense/annealment/rockwell rating/flipity dickity doodad whateverthehelluwannacallit state. I'll buy you a new(well, used) swan chisel to replace this one. Whattaya say?
Cheers to all. This wins my favorite thread of the month award.
Jeff
Jeff, if you're at all serious, I'm gonna pass. First, I'm not sure my chisel is a prime candidate for this test (I think it's soft and no good and the file test seems to agree, but I suppose I could be wrong). Second, I'm skeptical the testers would be willing to spend their time this way. Third, who would judge the results and on what criteria. Fourth, to be a fair test, the chisel would likely need to be sawn in half, lengthwise - a cut I'm not going to mess with, nor do I have a bi-metal blade. Yours is a fun idea but probably not realistic.
And I'm not worried about a replacement. My wife is always kidding me: "Oh look, another 'pointy thing' came for you in the mail!" I've got plenty of good chisels. And you know what's funny, there really is a significant difference in their ability to get and keep an edge. I have one (frankly ragged looking) old swan 3/8ths that cuts like no other chisel in my arsenal - through the hardest end-grain with ease and leaving a glassy smooth finish. I've not nothing different in sharpening it, so I'm guessing it's just a lucky find as far as theat steel.
Darn!
We're never gonna find how this works out!
Rich
Samson, my friend:
I wasn't expecting you to go through that rediculous process I prescribed. I simply was trying to let a little air out of the hot balloon.
I have neither the time nor the inclination to waste time trying to rectify a problem with a tool that can be replaced for $10 to $20 at a flea market. I was just poking a little fun at how serious it got around here.
When I was younger, I used to try to fix everything myself. I took it personally. As I got older, and a wee bit wiser, I realized how much more profitable it is to "outsource" a few of the demonic and archaic problems at hand. For me, replacing a tool not functioning correctly with a new one qualifies as "outsourcing the problem".
The only time I have to waste in my life, I spend either here or playing poker.
Have a good one, and good luck finding a replacement chisel for that softee.
Jeff
Pretty sensible idea! Just my bias, but I think that almost any hobby or professional woodworker would get a kick out of at least trying an experiment. Who knows, it might lead to making carving tools from old hacksaw or other blades, specialized lathe tools, doing a little forge work, or other pleasant diversions. It might also lead to a slightly better perspective on things that are often considered arcane mysteries, like sharpening, cryotreating and so forth. My very best story came from a guy I met who lived through one of the concentration camps by virtue of his ability to repair watch springs for the guards using a candle and a couple of tools made from old nails. Slightly more pressure doing a delicate local metallurgical manipulation!
My only caveat in all this is to avoid playing blacksmith with striking tools and anything where a fracture or a flying chip might be a possiblity of injury, machinery or auto parts,re-brazing carbide teeth on circular saws, and the like.
-Richard
Frankly, I don't think he owes you (or the other posters) squat! He is simply stating his opinion, which is exactly what internet forums are all about. Perhaps you'd care to scan some of your previous posts in this and other threads -- to me, they come across as arrogant and "know it all", quick to declare the error in everyone else's logic. The truths is, I am sure you know more than I (and probably more than a majority of posters here) but that notwithstanding, are you trying to impress us or educate?
Michael
I goofed up - this post was full of html tags and hard to read.copied below in post 63
Edited 1/4/2007 6:22 pm by eddiefromAustralia
Hi again,I pulled my Definition of Metallurgical Terms, published by the Australian Institute of Metals, 1971, who define decalescence as:"the absorption of heat which[sic] occurs when a metal or alloy is heated through its transformation range."This shows on a calorimeter as a change in slope vs time at constant heating rate.The decalescence is the amount of heat released.The temperature range over which it is released depends upon the alloy as you indicate. Looking quickly at the iron cementite equilibrium diagram here shows the temperature range at which ferrite transforms to austenite and vice versa, for a 1.2% carbon steel, to be between 723C and approximately 850C. It's probably semantics - is the decalescence point the temperature at which heat commences being released (Adam) or the point at which the heat finishes being released (Larry?) I'm not sure on this finer point myself. If I had to make an edjumakated guess, I'd lean towards the finishing point as it defines the temperature at which the phase change is complete and the total heat release can be calculated. In this case, the decalescence point is defined as the A3 (upper transformation temperature) for a particular steel, as used in the Machinist's handbook being quoted.Trust that this helps and doesn't further muddy the waters Cheers,eddie
Edited 1/4/2007 6:29 pm by eddiefromAustralia
Larry, thanks for taking the time to make your knowledge available. Very much appreciated. I know a couple of metalurgists who I'll ask about the "flux".
Wow, this post started something! I Teach in a public school. We make plane blades from O-1 and A-2 steel along with cold chisels from water hardening steel. While I certainly respect the science (it got us where we are today), there is room for traditional methods. According to the Directory of American Toolmakers, James Swan Co. started making tools in 1877. You can assume that the science was in its infancy then and Swan chisels are highly respected tools even today. Imagine how the heat treating was done at that time.
Our heat treating process is as follows:
1. Heat above the critical temperature in the forge (coal fire).
2. Judge the temperature by color and magnetism.
3. Quench in the appropriate medium (oil, air, water) to harden.
4. Immediately temper using a propane torch and temperature indicating stick. We temper the cold chisel by traditional methods using temper colors and the forge.
We have made thousands of tools over the last 30 years and as you can imagine, students are not always precise in their judgement of temperature. As with everything else in life there is room for error. Probably the Swan chisel in question was originally heat treated in a manner similar to the above and could be re-heat treated by doing the same.
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