Chainsaw Bar Length By Log Calculator

It’s there, that log is bigger around than my bar is long and there I am standing above it on a downed oak limb. So you fire up the beast and get the nose digging and begin to cut across the log. I pray you have enough chain out to make it to the end before shutting down or getting thrown backwards. That split second pause illustrates why bar size is important relative to the wood being felled.

You need enough chain to extend past the far end, and you also need to consider how much of that chain will actualy be working. The saw comes with a bar marked “twenty-inches,” so everyone assumes they’re getting twenty inches of cut. That’s not what happens. Because part of the bar must be tucked away in the engine housing and covered by the clutch cover, the working bar has to do all of its work with just the part that sticks out. Use the calculator above. It’ll crunch the numbers for you and turn that nominal bar size into an actual cutting length. That’s the single largest cause of error among weekend woodcutters.

How to Pick the Right Bar Size

You need to decide how you will cut when you get down to usable length. Are you just bucking firewood where log lays flat and you make a straight cut? Or did you limb it after a mess of a storm cleanup, so there’s angle and shift in leverage? Those differences is accounted for in the tool; it applies factors depending on what kind of cut you’re making. Roll cuts use a much shorter bar length compared to a straight pass. Slice half way around, turn log over, then finish from opposite side. It is a simple trick that saves time and helps save saws. Move the wood, don’t need big bar.

The other factor is hardness of the wood. Pine (softwood) will cut quickly, while hardwoods such as maple or oak will drag on the chain and slow down the engine. In that case you would of prefer a shorter bar in relation to the log size as it allows the engine to keep up with the chain. Trying to feed a small engine with a long bar into green oak is a recipe for dissapointment. So the system takes account of this and suggests a safety margin. An additional inch of clearance makes the difference between a stalled motor and a smooth cut.

Another thing that confuses people is saw power class. That battery-powered tool may appear to have the same torque as a gas saw. But it doesn’t. Depending on what type of saw you’re running, say, a compact electric versus a heavy-duty gas engine, you can use a shorter bar and must goes easy on it. Does it have sufficient headroom? Are you forcing the machine beyond its capabilities? The calculator will compare your saw’s class to the requirements of your cut and let you know.

But there’s more than just theory with safety margins. In reality, logs aren’t uniform cylinders; they have knobby ends, dip down in the middle, and twist weirdly. A couple inches of added margin when you think about what length you need allows for all this. It gives the chain enough room so that it doesn’t fully embed into the wood, decreasing the chances of kickback and ensuring a clean cut. You don’t want it scraping along the wood; you want the bar tip to clear it comfortabley.

So what’s the bottom line? The bottom line is: A bar is a mix of various factors. You want the shortest bar that will work well. So how long is short enough? It must be long enough to get the job done well. But longer means it gets heavier; it’s more difficult to control; it’s also more likely to kick back on you at the end. When you factor out the kind of cut and kind of wood used to make the bar shorter or longer, you eliminate the guessing game. You go from reading a label on a box to looking at the metal in your hands. And that’s when cutting becomes a confidence move instead of a stressful guess.