I started out with an old Colling hatchet. The head was securely attached to the handle.
I buried the head of the hatchet up to the eye in the soil.
I then built a fire on top of it. The fire was large enough to cover the head. The wood used was oak. I continued the burn for 15 minutes.
I then pulled the head out of the fire. The handle had burnt off, but surprisingly, the head appeared untouched by the fire in the areas that were buried.
I used a piece of split wood that I had left from making the fire, and with the help of a baton, I pushed the handle through the eye from the bottom. As you can see, the area on top of the eye was not too charred, ut the bottom part had been burnt much more severely. To punch out the part of the handle in the eye, just prop one end of the head on the ground, and the other end on a log. That should create enough free space under the eye for you to push it out.
With very little effort, the head of the axe was free from the handle.
When I returned home, I sanded off some of the paint/protective cover, and put the head in vinegar. What that does is to reveal the temper line of the axe head. Here it is clearly visible, and seems unchanged. At the very least, there are no areas where you can see that high heat advanced and changed the temper. It is possible that the temper was uniformly changed throughout the head, retaining the temper line, but I hav eno way of testing for that.
I was shocked by how little the head was effected by the fire. Most of it retained its original paint, and even the rust appeared to be untouched. While the head got hot, it never even came close to being hot enough for the temper to be substantially effected. Even the poll of the axe, which was directly exposed to the flame, never got red hot. Despite my scepticism, this appears to be a very effective way to remove an axe handle while in the woods.
Good one. I have always used this method with the stubborn ones at home.
ReplyDeletehttp://woodsrunnersdiary.blogspot.com/
I've heard of that method, but never seen it done and the results of it.
ReplyDeleteI don't recommend this method as it could alter the temper of the axe head.
ReplyDeletePosted before I was finished.....
ReplyDeleteEven if the poll was not red, the sides of the eye are much thinner and do not require "red hot" heat to alter the temper.
Well, the temper of the poll is not usually of interest, as it is not intentionally tempered to begin with. The usual problem is the temper of the bit, as that is the part of the axe which requires specific hardness. In the above test, it was not effected.
ReplyDeleteAside from that, from what I know in order for the temper to be readjusted, you have to heat up the metal until you see changes in color. At least that is how they used to measure the hardness in the past (changes in the color). I was not aware that the temper can be changed at such low temperatures.
Ross, I'm afraid you're incorrect. There can be significant changes in temper without the colour of the metal changing at all. Just ask a knifemaker how he tempers his knifes after the initial heat treat. Also the poll is not intentionally hardened, depending on how the axe head is tempered the poll may be tempered. Also you have not got any evidence that the bit was not affected. As you say, the whole axe may now be softer.
ReplyDeleteAs you are clearly not worried about damaging this axe I would say that to test the hardness of the bit you should use a metal file. If the file bites deeper than it did before you burned out the axe head then you will know you have softened it. As you can't go back in time to file the un-fired axe head I would suggest you compare it to another axe you know to be of good heat treat.
Also the colour change you are referring to was used to assess when to quench the metal for optimal hardness, not to see how much it had been softened.
Dave
Hi Dave,
ReplyDeleteThere is not much more I can tell you other than what the pictures show. Like they say, "If ifs and buts were candy and nuts, then every day would be Christmas".
The reason why I did the test is that I've seen it shown in a number of books from very well respected authors from the early 20th century, including Kephart. It appears to have been a widely used method of handle removal by past generations. I figured there might be something to it.
I can not detect any difference in the temper with a file (doesn't mean there isn't any, I just can't tell). I did this with another head as well, with similar results. The head never got hot enough for the paint to blister. The temper line remained the same after the burning. While it is theoretically possible that the temper of the whole axe would change while keeping the temper line intact, it is a real long shot considering that it is being directly heated only at one end.
As far as judging hardness by the colors, my point was that as you said, they would heat it up to the desired color and then quench it to get the desired hardness/temper. A change in color was required either way. Does that mean that you can't change the temper at lower temperatures? No. It is in theory possible, although few people seem to actually know what that temperature is.
With respect to the poll, any tempering is usually incidental. Most often an effort is made to keep the poll soft, which the above buring would not change. I would not worry about it at all.
There is nothing else I can think of to test the change in temper. If you do not find this test satisfactory, then there isn't much more I can do with the technology at my disposal. All I can say is that theoretical arguments aside, the results are what they are. Use them as you see fit.
"As far as judging hardness by the colors, my point was that as you said, they would heat it up to the desired color and then quench it to get the desired hardness/temper. A change in color was required either way. Does that mean that you can't change the temper at lower temperatures? No. It is in theory possible, although few people seem to actually know what that temperature is. "
ReplyDeleteRoss, I'm afraid you really are wrong on this. Hobbyist knifemakers regularly temper blades in kitchen ovens.
When one quenches steel there is a crystallographic transformation from austenite to martensite, that is from the face centred cubic structure to the body centred tetragonal structure. This is caused by shearing forces during rapid cooling. Martensite is inherently brittle which is why quenched steel is normally tempered.
Tempering is the process by which the temperature of steel is raised to allow the relaxation of some of the martensite, a non-equilibrium species, to ferrite (face centred cubic). This actually occurs at room temperature, but at such a slow rate that it is negligible, the effect becomes noticeable as the temp is raised. Two tempering cycles of 2 hours at 205 celsius (400 F) will bring O1 steel down to the high 50s, assuming a good quench prior to this. Tempering can be carried out for longer time periods at lower temps or more quickly at higher temps.
I fully believe that you may not be able to detedt any difference in the hardness, but I am fairly sure that there is some, though probably not very much. This difference is negligible this time, but if this method is repeated a sufficient number of times I am fairly sure that you will eventually anneal the axe head. Just in case there is any question of my qualification to speak on this, I have a masters in Materials Science and am working on my PhD.
All the best,
Dave
Dave, I have to say, I’m not really sure exactly what you are arguing about here, or about what you believe me to be wrong. I did an experiment, I documented the procedure, and I showed you the results. They are what they are. Like I said, take it for what it is. The results are not going to change based on what it says in a textbook, and while I appreciate your expertise, they do not make the axe any softer.
ReplyDeleteI put the axe in the ground, I burnt out the handle, and there is no noticeable change to the temper from a practical standpoint. I don’t know what a textbook says the results should be, but these are the result I got. That’s all I can say about it.
My interests in this procedure are practical, not theoretical. All I care about is, whether the axe will chop just as well after the procedure as it did before. It seems to do just that. That is all I have stated in the above post. I don’t know how I can be wrong about that.
Whether or not there is any marginal change that I can not detect, or whether after a hundred or a thousand or a hundred thousand burns there will be a noticeable change, I don’t know. All I have are the results I have outlined above, and they show what they show. Draw whatever conclusions you wish from them.
Ross... When will you start forging axes. You know you want to.
ReplyDeleteGood Luck
:) I wish!
ReplyDeleteMy point is that there is a difference, whether you notice it or not, I find it misleading for you to make the statement that you have not damaged your axe.
ReplyDeleteDave
Dave, if your argument is that there will always be a marginal change in the temper of a piece of metal when it is exposed to any temperature other than absolute zero, with said temper being more effected at higher temperatures than lower ones, then fine. While I don’t know if that is in fact the case, I don’t care enough about it to have a fight over it. I'll take your word on it.
ReplyDeleteNow, does that have any practical application to whether or not your axe will hold a good edge after you remove the handle in this manner? Not that I can see. At least, neither of us can tell with the resources available to us at this point.
There are many things that technically happen in the woods, which have little practical bearing. Every time I chop with my axe, I am damaging both the head and the handle. TECHNICALLY. What does that mean about me using the axe? Nothing! There are only so many disclaimers I can provide.
How about this. I’ll change the post to say that “While the head got hot, it never got hot enough for the temper to be SUBSTANTIALLY effected”. I hope that will make everyone happy and end this pointless back and forth.
Just as before, if you can come up with some actual way to test the effects of the process, I would be happy to repeat the test. I am not married to this approach, I’m just telling you what I see. If it doesn’t work, I would be happy to report those results as well.
Hi Ross,
ReplyDeleteAs I can tell I have upset you please accept my apology as that was not my intentions. I enjoy your blog and have actually been enjoying this conversation, I am sorry you have not. I come from a background of heated scientific debate and often forget that not everyone enjoys this.
I believe that if this method is carried out a number of times you will notice the difference. As I said on BCUSA, I am working on accessing a rockwell tester, but do not know if I can pull it off.
As you say, every time you chop you are damaging your axe, however that is normal wear and tear in the tool, it is inevitable. The difference for me is that this is not inevitable damage.
I am not trying to make you change your post, I wanted to make you aware of the fine points of the matter. I felt that you would be interested as from what I read on your blog you are an inquisitive and intelligent person. I am sorry that I haven't managed to do this in a non-confrontational way.
In terms of testing this approach, it may be very time consuming and may ruin the axe head, but would you consider repeating this 5 more times to assess the outcome? I would suggest that you test the hardness with a file after each fire. I would also say that you conduct 5 individual fires as the slow cooling after the fire goes out also affect the steel. What do you think?
Dave
Dave, was that an email you just sent me? If so I deleted it because I though it was a comment. :(
ReplyDeleteNo worries. I'll try to do the heating several times and see. It will be subjective, but I would be happy to give it a try. I have no problem with ruining an axe head.
Oh, in case anyone is interested in the comments made to this post on Bushcraft USA, you should take a look here: http://bushcraftusa.com/forum/showthread.php?t=34561
ReplyDeleteIt's getting to be a long thread.
Hi Ross,
ReplyDeleteI think it was a comment, but I might have hit the wrong button. Sorry. Did you manage to read all of the post before it went the way of the dodo?
Dave
:) Yes, I read it in my email. Ha, now no one will know what we were talking about.
ReplyDeleteWhat's more I can't remember exactly what I typed, so there will never be an exact duplicate!
ReplyDeleteDave