
Originally Posted by
Col.Coleman
I wasn't putting you down mate, I could just see the thread degenerating into a mud slinging match because someone mentioned chaps, ala the thread I highlighted.
Now in answer to your question.
Chainsaws cut by small chisels revolving at high speed linked into a chain. Now every so often, these chisels hit something that make the chain stop. But the chain carries inertia, and the powerhead still trying to rotate the chain causes the saw to try to to rotate itself. Just like a stuck drill bit and a drill.
Now depending on which way you are cutting to what the saw does. If cutting on the bottom of the bar, downwards, the powerhead drops and the blade comes back at you intent on removing your face, because as the saw rotates it normally frees itself and starts spinning again. This all happens in a fraction of a second. When you are cutting in this manner, the chain brake is supposed to hit your hand and move forward and brake the chain. In theory. Depending on the size and power of the saw and blade to how bad this can be. More of either magnifies the results. Hence a face mask and helmet is recommended, as well as saving your face and eyes from swarth from cutting, or things falling on your head. Add in ear muffs to protect your hearing. Gloves and a vest are also a good idea.
The chain brake on the more modern saws also have an inertia switch built in so you hand doesnt have to hit the brake handle but if the saw is kicked with a set amount of force it triggers the sprung catch and the handle is thrown forward.
Now if cutting on the top of the bar, upwards, the powerhead goes up, the blade comes down and tries to turn you into an extra for an Errol Flynn movie. Hence the recommendation of chaps and boots.
The most common way that people injure their legs is either drop starting or they dont pay attention to where the chain is (normally when stepping away from the log with the chain still spinning) and nick thier leg.
If the cloggers/chaps were not worn, the chain tries to bury itself into the flesh and before it is normally realised that it has happened it has got to bone causing major damage to muscle and nerves etc.
The chaps and vest protect you by being designed in such a way that if the outer layer gets cut through, it is filled with a fibrous material that will snag the chain to stop it moving and hence cutting any further.
The whole point of this is to protect yourself, as you never know when this is going to happen. It is more likely when you are inexperienced, using high powered saws, have been cutting for a long time and get tired, some tree hugging hippie has spiked a tree or whatever. Now it is not always practical to don all such epuipment but you must realize when you don't you must accept the risk you face if something goes wrong. It is up to each operator to decide for themselves, except in the case of OH&S where the decision has been made for you whether you like it or not to protect some organisation from being sued if you hurt yourself.
Saws are a very dangerous thing when something goes wrong, novice or experienced. Best advice is to suit up before you use, but ultimately it is your call. Respect what you are using, just like you would your firearm.
CC
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