Keeping Your Chain Saw Sharp

Image Gallery STEVE MAXWELL

Using a chain saw significantly cuts the time and energy devoted to homestead chores. But that's only true if the saw's chain is sharp. A dull chain saw is about as useful for cutting wood as a plastic spoon. To cut quickly and safely, saws must be sharpened often. With a few simple tools, here's how you easily can do it yourself.

Successfully sharpening a chain saw involves three steps: shaping the chisel-like teeth that cut wood (they're call cutters); adjusting the parts of the chain that regulate the bite taken by each cutter (called depth gauges); and fine-tuning the tension of the chain so it runs freely, with no slack, around the bar. Think of a saw chain as a linked row of small chisels. Each cutter is a chisel it takes a bite as it travels across the wood. If all the bites are crisp, equal and even from side-to-side, you've got a hungry, smooth-running and well- sharpened chain.

Tools of the Sharpening Trade

While I was a university student during the early 1980s, I worked part time for a Mennonite farmer named Paul. His ancestors settled the land in 1816, and preserved a magnificent maple sugar bush while other pioneers slashing and burning like mad. When we weren't making maple syrup, we cut firewood for sale from a forest that included century-old maples big around than trash cans.

Sharpening chain saws was Paul's exclusive job, and I soon understood what a really sharp saw could do. He used only a round file, a vise welded the bucket of his tractor, and a well-trained eye to get results that sent long curls of wood showering out of the saw he gave me to cut through oak, oral and hickory. Using a file freehand looked easy, until I attempted to sharpen my own saw a few years late) spent hours trying to succeed, yet still had a saw with no appetite for work.

But all that changed when I bout some tools to help. Choosing the right is the first step to hone; your chain saw sharpening skills. And unless you want to spend years training your eye to guide a file without help, that means more than just a round file. But not much more. Here are the tools you need for successful sharpening:

• a filing guide and round files
• a depth-gauge guide and flat
• a stump vise (optional) for in the field sharpening

The type of filing guide I recommend, shown in the Image Gallery, is made several manufacturers. It clamps to the chain bar and regulates the travel of a round file over the cutters. Consistent filing strokes in the correct direction lead to a sharp saw chain, and a filing guide reliably serves this function.

You'll also need a sharp round file to fit the filing guide, but it has to match the size of your chain. Cutters are usually designed to be sharpened with 5-inch- or 7/32-inch-diameter files. Either your owner's manual or the saw-chain instruction sheet that comes with a new chain lists what's needed. Replace the file every five or six sharpenings for best results, and don't let your new files clang around in a toolbox unprotected, which dulls them as quickly as hard use does. Wrap each new file in cloth, after coating it in a lightweight machine oil, such as 3-in-One lubricating oil. That way they'll stay in top shape, ready for use.