How to Wind a Trimmer Spool (Single & Dual Line)

Buying pre-wound spools is convenient, but winding your own from bulk line costs a fraction as much and takes about two minutes once you know the trick. The catch: a sloppily wound spool is the number-one cause of line that won’t feed. This guide covers both single- and dual-line spools and the small details that separate a clean-feeding spool from a jammed one.

First, get the right line

Before you wind anything, confirm the line diameter your trimmer is rated for — commonly 0.065”, 0.080”, or 0.095”. Using line that’s too thick is the single most common cause of feed jams, because it binds in the head’s eyelets. If you’re unsure, see Choosing Trimmer Line Gauge. Cut 10–20 feet of fresh line; old line stored in sunlight gets brittle and snaps.

Step 1 — Find the wind-direction arrow

Every spool is molded with an arrow (and often the word “WIND”) showing which way the line goes on. This matters: wind against the arrow and the line will never feed, because the head spins the spool the other way. Anchor the line end in the small notch or hole at the spool hub.

Step 2 — Wind tight, flat, and even

Wind in the arrow direction, keeping each wrap tight and flat against the last — even layers, no crossing over. Loose or criss-crossed coils trap each other and, under cutting heat, the layers literally weld together and stop feeding. Keep tension on the line with your free hand as you wind.

Step 3 — Dual-line spools

A dual-line spool has two separate channels divided by a center wall, and usually two anchor holes. Load both lines at once: fold a single length in half, hook the bend into the center, and wind both halves simultaneously, each staying in its own channel. Keeping them separate is what lets a dual-line head pay out two strings evenly.

Step 4 — Park the ends

Leave 4–6 inches of each line loose and hook the ends into the retainer notches on the spool rim. This stops the line unraveling while you reinstall the spool. Thread the loose ends out through the eyelets in the head, drop the spool onto its post, snap the cap on, and tug each line to release it from the notch.

Common mistakes

• Winding against the arrow — feeds nothing.
• Cross-winding — coils snag and jam mid-job.
• Over-thick line — binds in the eyelet (match your head’s rating).
• Overfilling — leave a few millimetres below the spool rim so the cap seats.

When to just buy pre-wound

If you burn through more than a spool a week, pre-wound replacements pay for themselves in saved time. Find ones that fit your trimmer on the Brands page or in the shop. If your line still won’t feed after a clean wind, work through Trimmer Line Won’t Feed: A Troubleshooting Checklist.