Chainsaw kickback.
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Bob Wright
Addicted to ArboristSite
Bring your camera i am sure we could do a live demo, with a dummy operator of course...Bob
Schultzz
ArboristSite Operative
Chainsaw Kickback Massacre
Knew two people that got their chainsaw stuck in their throat because of kickback. One is dead, the other is maimed for life. Get some training and learn why a saw kicks back. Be careful, or do something else.:chainsawguy: :chainsawguy:
Knew two people that got their chainsaw stuck in their throat because of kickback. One is dead, the other is maimed for life. Get some training and learn why a saw kicks back. Be careful, or do something else.:chainsawguy: :chainsawguy:
tree md
Addicted to ArboristSite
carvinmark
Addicted to ArboristSite
Kick back is a scary thing. For carving we use dime and quarter size tips to help reduce the possibility of this, but it still can happen.
Get yourself a pigs head and fix it firmly to post.
Apply running saw to line between the eyes down along snout.
The result should be a pretty close approximation - minus the blood.
If you want more action detail you can video it and play it back in slo-mo.
You can always add fake blood for more realism.
Apply running saw to line between the eyes down along snout.
The result should be a pretty close approximation - minus the blood.
If you want more action detail you can video it and play it back in slo-mo.
You can always add fake blood for more realism.
Woodie
"Cap'n Bullcrap'n"
I don't quite think he's looking for that kind of kickback video...
I think it's a good question...I've never gotten one (yet!!!), and I would be curious to see one just to get a sense for how the saw reacts physically.
I think it would be a good idea for one of the manufacturers to do a "crash-test-dummy" video of an actual kickback to give people a better sense of what could happen and how best to be prepared if it does.
And just to head-off the inevitable reply, yes, I agree...there are several members here I would LOVE to see play the part of the dummy! :hmm3grin2orange:
cityboy
ArboristSite Operative
Haven't actually done it myself either, but I suspect their are infinite degrees of kickback force depending on several factors: How fast the chain is running, how fast and hard you jam it into the resisting object, how much of the 'kickback zone' you jam in, how sharp the chain is, how good a grip you have on the front handle, how strong you are, and how prepared you are for the reaction force, to name just a few.
So creating a video that demonstrates this hazard would only be able to show one combination of these things, which couldn't possibly be realistic for all scenarios. Then in the good old USA the lawyers would get a hold of the video and explain how the manufacturer didn't properly warn the user because the video didn't show nearly as violent a kickback as their dead client experienced, so he wasn't properly warned and therefore its the mfr's fault he's dead.
I prefer to take the approach of assuming any kickback will fling the saw around towards my body and cut me in half, and don't need any video to show me what the final result might look like. I just keep the frigging kickback zone as far from hard objects as I can. I suspect in reality, I could probably gradually ease the kickback zone into something and make the saw jump just enough to scare the crap out of me, but I'm not going to try that anytime soon. I still have to master the beer bottle opening trick first.
troutfisher
Addicted to ArboristSite
I don't have any videos, but I have been cut. The Kickback I expirienced was Explosive and Violent. It stalled the saw. The saw tries to rotate, it tries to do a "backflip" in your hands. Your curiosity is a good thing, do everything you can to learn about it, prevent it, and be ready when it happens. Not IF, WHEN. Stay Safe.
I had a nice kick back the other day and it was totally my fault it happened. I was working on a new 5000 I had just picked up and Thank God it was only a 50cc saw (that I found out the chain brake DIDN'T work on) the hard way. But that sucker kicked straight back, up wards, rotating back, with bar and chain coming back toward the Ole noggin to the right side of me.
Was a wake up call to say the least, to pay more attention working on and tuning saws.
Cut safe.................
What casues kickback?
OK - I have never seen or felt kickback. I have only ever heard about it. I have read descriptions of what causes it but I couldn't recite what causes it, off the top of my head. I have NO professional chainsaw experience and my "training" has been just informal mentoring. I first used a chainsaw in about 1984 and have owned one, or more than one, since 1997. 95% of my experience has been on the ground. A large percentage in hurricane cleanup, land clearing and misc stuff here and there. I feel I'm more experienced than most non-professionals and I have even, informally, trained a few others on safe operation. (Had a booklet and did cover kickback)
Maybe my informal training has been good and I am operating the saw safely and properly. I pride myself on having good, properly functioning, equipment that is sharp. I do not use "safety" chain.
Anyway - If someone here could explain the dynamics of chainsaw kickback, what causes it and how to avoid it, I would appreciate it.
OK - I have never seen or felt kickback. I have only ever heard about it. I have read descriptions of what causes it but I couldn't recite what causes it, off the top of my head. I have NO professional chainsaw experience and my "training" has been just informal mentoring. I first used a chainsaw in about 1984 and have owned one, or more than one, since 1997. 95% of my experience has been on the ground. A large percentage in hurricane cleanup, land clearing and misc stuff here and there. I feel I'm more experienced than most non-professionals and I have even, informally, trained a few others on safe operation. (Had a booklet and did cover kickback)
Maybe my informal training has been good and I am operating the saw safely and properly. I pride myself on having good, properly functioning, equipment that is sharp. I do not use "safety" chain.
Anyway - If someone here could explain the dynamics of chainsaw kickback, what causes it and how to avoid it, I would appreciate it.
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cityboy
ArboristSite Operative
Its pretty simple really, a force in a given direction will create a counter force in the opposite direction. Add some resistance to that force, and the counter force will also increase.
Given that, look at how the chain rotates around the bar. At the bottom of the bar the cutters are moving towards you. If they encounter resistance coming towards you, they create a counter force pulling away from you. If you're holding on with both hands its not a big deal, because the weight of the saw plus your normal grip will easily counter that force. Same thing if you cut with the top of the bar, but now it will push towards you. In both of these cases the force is pretty much parallel to the bar so if you're holding it horizontal there's no vertical forces involved. You'll have easily enough strength to overcome those forces because your arms are strong enough in that direction and there's no rotational leverage applied by the counter force.
At the bar tip things change quickly. If you cut with the bottom half of the bar tip the teeth are running at a 45 degree angle (as a crude approximation for the discussion) down and towards you. So the counter force is now a combination of up and away from you. The fact that the counter force is partially pulling away from you makes that zone somewhat tolerable, because you won't get the strong rotational force like in the kickback zone (to get a little more technical the force is not tangential to the handle, so the rotational force is reduced considerably). You still need to use caution in that area because things can change quickly.
Also, going off on a bit of a tangent, I think this might be why the chain rotates the direction it does because this zone would be the kickback zone if the chain rotated the other direction. That would be harder to avoid since we're generally cutting down rather than up, and our arms have little strength resisting the down and back forces that would be propelling the saw towards our ankles. That would make for an even more dangerous kickback zone than the one we are faced with now.
So, finally getting around to it, the 'kickback zone' is the top half of the bar tip. Here the cutting force is going down and away from you, so the counter force is upwards and towards you, and is tangential to the handle, so the rotational force is greatest at this point. That counter force will try to spin the saw up and towards you as if someone standing in front of you kicked the end of the bar up while you hold the saw. Its a very strong force, with a lot of rotational leverage and your arms are in a position where they aren't as strong resisting the rotational force as they are the pure horizontal forces. The result is the bar flips back into your shoulder or head depending on where you are holding the saw.
spacemule
The Peanut Gallery
Take a look at member Oregon Engineer's posts. He has posted a lot of good information.
kickback video
kickback injury
chain shot slideshow
chainsaw injury locations
kickback video
kickback injury
chain shot slideshow
chainsaw injury locations
Woodie
"Cap'n Bullcrap'n"
Thanks for diggin those up, space...great info!
And thanks for a good explanation too, cityboy!
2000ssm6
Stihl User
Fuzly
ArboristSite Operative
I just had a close call yesterday. Luckily, I had just let off the gas. I was getting ready to move, I was in a hurry, and started moving with a coasting chain all at once.
I'm still not sure what I hit, but it felt like the saw was going to flip out of my hands over my right shoulder.
I'm over 200 lbs., and in good shape, but I don't care how strong you are, if it's a full fledged kickback you better have your important parts out of the kickback zone. Thank God the chain was starting to coast and not under full power.
So I took a break, thanked the big fella upstairs, checked my drawers, and went back to work at a slow and deliberate pace.
I've heard some instructors intentionally cause a "controlled" kickback to give the students some idea what to expect, more power to them-no thank you for me.
rguseman
Addicted to ArboristSite
I have to say that as a guy who is not a professional but has probably a little more experience with a chainsaw than the average homeowner you guys have scared the bejesus out of me. I have had couple of times where the tip hit a piece on the other side of the cut and jumped a little bit but nothing like what is being described. I understand the science behind the kickback and basic safety (two hands on the saw, firm grip, paying attention to the job at hand, etc.) but I wondering if the professionals could maybe give a few examples of situations that could lead to kickback or at least a good safety video/book so that some of us non-professionals can check ourselves. I hope that this is not too remedial of a question. If it is, my apologies.
ropensaddle
Feel Lucky
Keep the bars upper ninety degree quadrant from making
contact and you wont have kick back. Also make it a practice
to keep your arm locked as in that position if kickback occurs
it will tend to push you away from bar! This is one reason
I seldom bore cut as it is asking for a server kickback!
contact and you wont have kick back. Also make it a practice
to keep your arm locked as in that position if kickback occurs
it will tend to push you away from bar! This is one reason
I seldom bore cut as it is asking for a server kickback!
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Tree Sling'r
Addicted to ArboristSite
Wrap you thumb is the number one saftey rule when running a saw, it will help prevent many injuries, but not kickback.
