When a chainsaw chain sustains damage, such as a cracked drive link or stretched component, a homeowner often needs to shorten the chain by removing the compromised section. This repair process is also necessary when resizing an older chain to fit a different bar length or when replacing a damaged part to prevent further wear on the sprocket and guide bar.
Essential Safety and Preparation
Before beginning any work on the chain, prioritizing personal safety is paramount. Heavy-duty work gloves and impact-resistant eye protection must be worn to shield hands from sharp components and eyes from flying metal fragments during the removal process. The chainsaw must be completely powered off, and a secondary precaution involves disconnecting the spark plug wire to prevent any accidental startup of the engine. Engaging the chain brake also helps secure the assembly.
Preparing the saw involves loosening the two bar nuts that secure the clutch cover to the powerhead. Once the nuts are loose, adjust the chain tensioning screw counterclockwise to release the necessary slack in the chain. This allows the guide bar to move closer to the powerhead, making it possible to safely lift the chain off the drive sprocket and remove it from the bar channel. The detached chain is then ready for link repair on a stable workbench.
Gathering the Necessary Tools
Removing a chain link requires specialized tools to successfully break the hardened steel rivet pin that holds the links together. The most efficient method uses a dedicated chain breaker tool, which mechanically pushes the rivet pin out of the side plate with a precise, threaded plunger.
For those without the specialized tool, an alternative setup involves securing the chain in a sturdy bench vise. The manual removal method requires a ball-peen hammer and a metal punch sized slightly smaller than the rivet pin itself. Since the rivet head must be removed before punching the pin out, a rotary tool fitted with a grinding stone or a small angle grinder is also needed. Finally, the repair requires a replacement rivet link, often sold as part of a small chain repair kit, to rejoin the two halves of the chain.
Step-by-Step Link Removal
The first physical step involves locating the specific link that needs removal, whether it is damaged or simply part of a section being shortened, and identifying the rivet pin that must be driven out. When a specialized chain breaker tool is available, the process is streamlined.
Place the chain onto the tool’s anvil and align the plunger directly over the rivet head. Turning the tool’s handle applies force, slowly pushing the solid pin through the side plate and separating the chain with minimal effort.
For the manual removal technique, clamp the chain securely in a bench vise with the rivet head facing upward and positioned just above the vise jaws. The flared head of the rivet pin must first be removed using a rotary tool or grinder. Perform careful, controlled grinding until the flare is completely flattened, ensuring the grinding only removes the head and does not damage the surrounding links.
After the rivet head is removed, reposition the chain so the exposed, ground-down pin is supported by the vise jaws, allowing a clear path for the punch. Place the metal punch directly onto the center of the pin, and use a series of sharp, controlled strikes with the ball-peen hammer to drive the pin completely out of the side plate. The force must be sufficient to eject the hardened steel pin without bending the punch. Once the pin is removed, the damaged link falls away, leaving two separate ends of the chain ready to be rejoined.
Reconnecting and Tensioning the Chain
With the unwanted link successfully removed, the two free ends of the chain must be connected using the new replacement rivet link from the repair kit. Insert the replacement link through the holes of the final drive link and the first cutter link, then place a new side plate over the exposed pins. The new pin is designed to be spread or “peened” to secure the side plate.
Peening involves supporting the chain on a solid surface, such as the anvil of the chain breaker tool or the flat surface of the vise. Use the ball-peen hammer to gently strike the two exposed pin ends to flatten and flare the metal, locking the new side plate firmly in place.
After the repair is complete, reinstall the chain onto the guide bar, ensuring the cutter links are facing the correct direction, and place it around the drive sprocket. Set the chain tension before fully tightening the bar nuts. Use the tensioning screw to move the bar outward until the chain fits snugly against the underside of the guide bar. A correctly tensioned chain should allow the drive links to be pulled free of the bar groove by hand with only moderate effort. Once satisfied, tighten the bar nuts completely to lock the bar in place.