Spacemule is on my ignore list so I can't quote him but I was able to read his post thanks to Euroford. Space you are once again absolutely wrong when it comes to working a falling saw. A short bar is a recipe for disaster when teamed up with a big powerfulm saw. For instance a 16" bar on a MS660 will be one heck of a kickback hazard compared to a 36" bar.
Stick to what you kanow which is... I don't know what.
How quaint. I can dog you at will and you will not see it. I don't mind if you discount what I say, but you merely make a fool of yourself when you do so without justification or basis. I provide this response for any others keeping up with this discussion.
Your statement that a 16" bar on a 660 is a larger kickback hazard is completely wrong, and I'll illustrate why. But first, let me ask everyone this. What do you do when you are loosening a nut that will not budge? Have you ever gotten a "cheater bar" to break nuts loose? Longer bars posing more danger works on the same principle.
Let's take two arbitrary bar lengths, say 16" and 28". Now, for all intents and purposes, the chain speed will be constant between the two bar lengths for a given saw.
Now, we need to understand kickback. Kickback occurs when the bar tip comes against an obstruction and forces the tip of the saw up and back towards the operator.
As you can see, your hands are holding the rear of the saw and acting like the bolt you had trouble breaking loose before. The upward force on the bar is transferred as torque through the bar into the handles and you must hold the bar in place. Given that the chain speed is for all intents and purposes constant between bar lengths, the upward force on the tip of the bar will be the same in a kickback situation whether the bar is 16" or 28".
Now, we've said that torque is transferred through the bar into the handlebars on the saw. But, just what is torque you say? Torque is a rotational force multiplied by a distance. Let's take an arbitrary amount of force for illustrative purposes, say 50 pounds. We've already decided that this force will be the same between the bar lengths. So, the question becomes, how much torque is applied to the handlebars with a 16" bar versus a 28" bar?
Easy. While the rear of the bar is not the pivot point, we can use it for comparison, again merely for illustrious purposes. A 16" bar with a 50 pound kickback force at the tip will apply 50 pounds x 16", or 800 inch pounds of torque at the rear of the bar. A 28" bar with a 50 pound kickback force at the tip will apply 50 pounds x 28" or 1400 inch pounds of torque at the rear of the bar.
That's right folks,
almost double the kickback torque that your hands must hold steady. The longer bar is a "cheater bar" of sorts and it will be more difficult to control in a kickback situation. Furthermore, I cut a lot of wood with a 20" bar on my Husqvarna 394, and I can tell you from personal experience that real life bolsters the physics facts I've alluded to. Furthermore, the longer bar is more apt to inadvertently be touched against a log unintentionally, further compounding the dangers of a longer bar.
Now, you can argue with me all you want, or disagree. I don't mind one bit. But please realize, arguing with the laws of physics only makes you look a fool.
