Sharpening Your Saw Chain Skills

My Dad worked for the family business for nearly 40 years. During that time, he hand-filed nearly every saw chain we sharpened, whistling while he worked. He often joked that he was “on his second million feet of chain.” While working alongside him, I learned a few things about the art of sharpening saw chain. 

First, let’s look at cutting dynamics. Each cutter on a saw chain functions like a planer, removing a thin shaving of wood as it travels through the kerf (cutting channel). A sharp cutter produces long wood curls. As it dulls, those curls become chips as the cutter begins chiseling rather than cutting. Watching the chips your saw produces is one of the easiest ways to evaluate chain sharpness. A photo of this is below. 

Next, it’s important to understand the basics of saw chain construction. The cutting edges are protected by a hard layer of chromium, which gives the chain its ability to hold an edge. As the chain dulls, that chromium wears back from the cutting edge, exposing the softer steel beneath. Sharpening simply means removing enough material from each cutter to reach fresh chromium again. 

In the center picture of a dull cutter below, the key is the bright section along the cutting edge. The chromium has worn away, exposing the softer steel beneath. Continue filing until that bright section disappears, leaving the cutting edge clean and uniform, as shown on the picture on the right. 

Figure 1. Comparison of a sharp cutter (left), dull cutter (center), and properly sharpened cutter (right).

A properly sharpened cutter should have a clean cutting edge, a clean gullet (the round area of the cutter where the file runs), and a cutter angle that matches the guideline etched into the back of the cutter, which also serves as a wear indicator. 

Sharpening saw chain takes practice, but it's worth the time investment. A sharp chain cuts faster, places less strain on your saw, and ultimately makes it safer to operate. Today, my Dad has passed the file to my daughter, who now handles much of our saw chain sharpening. If you'd rather leave it to us, we can take care of it or replace chains that are simply beyond salvation. However, if you'd like to learn, stop by CRE! We're happy to spend a few minutes offering pointers, and we promise it won't take a million feet of chain to learn.