The Complete Handbook of Weed Trimmer Blades & Spools

Chapter 1: Understanding Weed Trimmer Blades & Spools

A weed trimmer blade or spool is, at its core, a consumable cutting head. One is a piece of rigid metal or plastic that cuts via momentum and sharp edges. The other is a housing of flexible polymer line that cuts via high-speed whipping. They accomplish the same work on the same machine, but their behavior in the field is radically different. Understanding that difference is the first step toward making good decisions about what to buy and how to use it.

Let's start with the spool, which is the more common of the two. A spool is a small reel, usually made of injection-molded nylon or a similar impact-resistant plastic, that sits inside the trimmer head. The trimmer line is wound around it, and the head holds it in place via friction or a spring-loaded bump feed mechanism. As the trimmer spins, the line is flung outward by centrifugal force. When you need more line, you tap the bump knob on the ground, which releases a small length of line from the spool. The blade of line whips through the grass and weeds at speeds that can exceed 200 miles per hour at the tip.

Line comes in a range of diameters, measured in inches, typically from 0.065 inches up to 0.155 inches or more. The diameter matters more than most people realize. Thin line cuts soft grass efficiently but fails quickly against thick-stemmed weeds. Thick line powers through brush and