Todays video is on axe handle breakage. There are many factors that can go into axe handle breakage. The thing people seem to look at and talk about the most when choosing axe handles, is orientation of the growth rings on the butt end of the handle. While that is a worthwhile factor to look at, it is far from the most important. Not only are There more important factors when it comes to the wood grain, but how we use the tool is also very important. The discussion of how to, and not to, use an axe re: handle stress and breakage is the real good stuff in this video.
While the wood and the design can be very important, user error still likely accounts for most handle breakage. Again, this is another area where blame is often misplaced. Most think of user error as hitting the handle on things. The usual term is overstrike, meaning basically you miss and smack the handle on the wood you are cutting. Overstrikes are a serious problem, especially in splitting wood, but how we swing an axe and whether our technique is light or heavy handed can be a major contributing factor to handle breakage.
Recently, I had a young man up here helping out. He wanted to learn about chainsaws and get in some saw time. So we headed out to cut up a black oak tree that had fallen in the road. I brought a maul with a wooden handle, because my usual fiberglass handled maul was out of commission until I could get the head epoxied back on. (Yes, I use a fiberglass handled maul. It is the only place I use that type of handle. It doesn’t feel great to use, but they are tough as hell. I’ve glued mine back on a few times and the handle is still going strong.)
The wooden handle on this maul was not very good. It was too curved for my taste and it had pretty strong grain runout. Runout means that the grain, instead of running all the way lengthwise along the handle, runs at a diagonal. Runout is a major factor in handle strength and strong runout is not desirable. But while this handle was kind of crappy and prone to failure, I had already used it quite a lot. Not only had I used it, but I also lent it to my land mates for a year or more to use. Then I used it some more last year and some more this year. AND, I also used it quite a bit that day, while my friend was getting in some time on the chainsaw.
But when I took over sawing some bigger, trickier cuts, my helper managed to break the handle in just a few minutes of splitting. That’s interesting, why? He didn’t actually hit the handle on anything. This is where we get into user technique.
Whether splitting wood or chopping, people have a misconception that they need to shove or push the axe head through the work. That is not how good chopping and splitting works. We have little ability to push on the end of an axe handle and do any work. Just try it. Put the end of an axe or splitting maul on a log and push on the end of the handle. You will find that you have a great disadvantage. The idea of putting an axe head on a long handle is to gain an advantage. If you want to see how important that advantage is, just grab an axe head with no handle and try chopping anything by just holding it in your hand.
So, we see that there is no advantage realized from that long handle if we just push on the end of it. The mechanical advantage of an axe is that when we swing in an arc, we can increase the speed of the head a lot.
The formula is MASS X VELOCITY = MOMENTUM. The mass, or weight of our axe or maul is fixed, but if we swing it faster, it can do more work. What we can change to be more effective by delivering more energy to the work, is increasing the speed of the head. Remember that point from this article if nothing else. If you want more power, concentrate on increasing speed.
The work of chopping or splitting should be finished by the time the bit of the axe hits the wood. It is folly to try to add more power by pushing the head through the work from the end of that long handle. Not to say that such an effort will have absolutely zero effect, just not very much. We have already seen that it is a very inefficient way to deliver energy to the work, but there are other reasons not to do it, namely handle shock, and to the point of this lesson, handle breakage.
Let’s go back to our earlier exercise, but use the law of extremes. Imagine what would happen if your axe handle was a twig. And you are going to push on the end of the handle again, while the head is resting on a log. You can imagine what will happen. The twig handle will bow downward, like a smile, then eventually snap. No one is smiling now. So that is the same type of bow stress we put on the wood when we push on the end of any axe handle. Also important is that when the axe head strikes the work, there is an equivalent of a backward force pushing the axe head away from the log. Any chopping or splitting is a sudden stress on the tool, when that head comes to a sudden stop in the work. So, stress is a given, but it can play out differently depending on what we as the operators are going to do while hanging on to the end of that handle.
Imagine if we were to swing the tool very fast, then essentially let go of the handle. It is not too likely that we will break the handle. The shockwave that travels through the tool can just play itself out. But, if we have a death grip on the handle and push on the end to try to drive the tool through the wood, it will play out differently. Not only can the shockwave work against the handle wood more if we are pushing on it, we are also adding even more stress. The head is jumping upward, while we are pushing downward, all emphasizing that bow shaped stress on the wood, and snap, time to replace our handle.
And those are the reasons why this particular maul handle, though vulnerable by design and wood quality, was able to survive much use, and also why it broke in short order when in the hands of an inexperienced user. This kid is very smart, but he is also young, strong and enthusiastic. Learning not to make this kind of misguided effort to drive the axe through the work takes either time or instruction. I still sometimes have to remind myself to lighten up and concentrate on increasing speed.
So, next time you are splitting wood, remember these take home points.
*The work of splitting or chopping should pretty much be done by the time the tool hits the work.
*Increasing speed is the main effective thing you can do to chop “harder”.
*Taking a death grip on the handle increases stress on the handle, and also transfers unnecessary shock to your body for no good reason.
*Taking a light grip on the handle will save out your hands and allow the shock wave from impact play out as it will.
*The mechanical advantage of an axe is in our ability to swing it in an arc of some description in order to increase it’s speed.
Happy splitting and stay safe.
