Introduction
Learning how to wind a double string weed eater is a fundamental skill for anyone who maintains a lawn or garden with a string trimmer. A properly wound spool delivers consistent cutting power, reduces line breakage, and saves you time on the job. This guide walks you through every stage of the process, from selecting the right line to troubleshooting common feeding problems. Whether you are a first‑time owner or a seasoned landscaper looking for a refresher, the step‑by‑step instructions and practical tips below will help you achieve a clean, reliable wind every time.
- Understanding Double String Weed Eaters
- Types of Trimmer Heads
- Choosing the Right Line
- Preparing for Rewinding
- Step‑by‑Step: How to Wind a Double String Weed Eater
- Two‑Line Method Explained
- Comparison Table: Single vs Double Line
- Tips for Longer Line Life
- Common Mistakes and How to Avoid Them
- Troubleshooting Feeding Issues
- Maintenance After Rewinding
- Frequently Asked Questions
- Conclusion
Understanding Double String Weed Eaters
A double string weed eater, often called a dual‑line trimmer, uses two cutting lines that extend from a single spool. The two lines rotate in opposite directions, which balances the cutting forces and reduces vibration. This design allows the tool to slice through thicker grass and light brush more efficiently than a single‑line model. The spool holds a length of nylon line that feeds outward as the tips wear down. Knowing the mechanics of the spool and the feed mechanism is essential before you attempt to rewind it.
Most residential trimmers feature a bump‑feed head: tapping the head on the ground releases a small amount of line. Professional models may use an automatic feed that advances line based on centrifugal force. Regardless of the feed type, the winding procedure is similar—what changes is how you secure the line ends and how much line you load. The following sections break down each head type so you can identify yours and follow the correct steps.
Types of Trimmer Heads
Fixed Line Head
A fixed line head comes pre‑loaded with a set length of line that cannot be adjusted. When the line wears out, you replace the entire head or the spool cartridge. This design is simple but less economical for frequent users because you cannot rewind the spool yourself.
Bump Feed Head
The bump feed head is the most common style on homeowner trimmers. Inside the housing, a spring‑loaded spool holds the line. When you tap the head against the ground, the spool rotates slightly, releasing a few inches of line. To rewind, you remove the spool, wind new line onto it following the directional arrows, and reinstall it. This head gives you full control over line length and type.
Automatic Feed Head
Automatic feed heads use centrifugal force to advance line as the trimmer spins. They often have a small window that shows the remaining line. Rewinding an automatic head is similar to a bump feed, but you must ensure the line is seated correctly in the feed slots so the mechanism can grab it. Some automatic heads require a specific line diameter; always check the manufacturer’s specifications.
Choosing the Right Line
Diameter
Line diameter determines cutting power and durability. Common sizes range from 0.065 in (1.65 mm) for light grass to 0.095 in (2.4 mm) for heavy weeds. A double‑line trimmer typically performs best with 0.080–0.095 in line because the two strands share the load. Using a line that is too thin can cause frequent breakage; too thick may jam the feed mechanism.
Material
Most trimmer line is made from nylon 6 or nylon 6,6. Some premium lines add a co‑polymer or a reinforced core for extra abrasion resistance. For general yard work, standard nylon works well. If you frequently cut near concrete, fences, or rocky terrain, consider a reinforced or “titanium” coated line that resists fraying.
Shape
Line cross‑section shapes include round, square, star, and twisted. Round line is the most common and feeds smoothly. Square and star shapes provide sharper cutting edges, which can slice through tough stems faster, but they may wear the spool’s eyelets more quickly. Twisted line reduces drag and noise, making it a good choice for noise‑sensitive neighborhoods.
Preparing for Rewinding
Before you start, gather the following items: a new spool of line matching the diameter and shape recommended for your model, a clean work surface, a pair of scissors or a line cutter, and the trimmer’s owner’s manual for reference. Disconnect the spark plug (gas models) or remove the battery (cordless models) to prevent accidental starts. Lay the trimmer on a stable bench with the head facing up. Remove any debris from the spool housing—grass clippings, dirt, or old line fragments can interfere with smooth feeding.
Inspect the spool for cracks, worn eyelets, or a damaged spring. If the spool is compromised, replace it rather than trying to rewind a damaged component. Check the directional arrows molded into the spool; they indicate the winding direction for each line. Most double‑line spools have two separate channels, each with its own arrow. Following these arrows is critical—winding opposite to the arrow will cause the line to feed backward and jam.
Step‑by‑Step: How to Wind a Double String Weed Eater
- Remove the spool. Press the release tabs or unscrew the retaining cap, then lift the spool out of the head housing.
- Clean the spool. Wipe away any old line remnants, dust, or grease with a dry cloth.
- Cut two equal lengths of line. Measure roughly 10–12 ft (3–3.6 m) per strand for most residential spools. Cutting both strands at once ensures they feed evenly.
- Insert the first line. Find the anchor hole or slot for line 1, thread the end through, and pull until about 2 in (5 cm) protrudes.
- Wind line 1 following the arrow. Keep tension steady; lay each coil snugly against the previous one without overlapping. Fill the channel until you reach the fill line indicator or leave about 1/8 in (3 mm) clearance from the spool flange.
- Secure the end of line 1. Snap the line into the retaining notch or tuck it under the spool’s lip as shown in the manual.
- Repeat for line 2. Use the second anchor hole, follow the second arrow (usually opposite direction), and wind the same length.
- Reinstall the spool. Align the spool’s drive tabs with the head’s slots, press it down until it clicks, and replace the retaining cap.
- Test the feed. Reconnect power, start the trimmer, and tap the head (bump feed) or let it spin (auto feed) to verify both lines extend evenly.
- Trim excess. If one line is longer, shut off the trimmer and pull the excess through the eyelet until both tips are equal.
Two‑Line Method Explained
The two‑line method refers to loading two separate strands into a single spool, each occupying its own channel. This arrangement balances the centrifugal forces generated during operation, which reduces wobble and extends the life of the head bearings. When winding, treat each channel independently: follow its dedicated arrow, keep the coils tight, and avoid crossing the lines. Crossing creates friction points that can melt the nylon and cause premature breakage. Some spools have a central divider; others rely on the geometry of the channels to keep the lines apart. In either case, maintain a consistent winding tension—too loose and the line will slip, too tight and you risk deforming the spool.
After winding, the two free ends should exit the spool through the eyelets positioned 180° apart. This geometry ensures that as the head spins, each line cuts on opposite sides of the rotation, delivering a wider cutting swath. If your trimmer uses a bump feed, the tap action releases a short length from both channels simultaneously, keeping the cutting width constant. Understanding this geometry helps you diagnose uneven line wear later on.
Comparison Table: Single vs Double Line
| Feature | Single Line | Double Line |
|---|---|---|
| Cutting swath | Narrower, typically 10–12 in | Wider, typically 14–18 in |
| Vibration | Higher, unbalanced forces | Lower, forces cancel out |
| Line consumption | Less line used per hour | More line used, but each strand lasts longer |
| Ideal use | Light grass, edging | Thick grass, light brush, larger areas |
| Rewind complexity | Simple, one channel | Two channels, must follow both arrows |
| Cost per spool | Lower | Slightly higher |
Tips for Longer Line Life
- Store line in a cool, dry place. UV exposure and moisture degrade nylon, making it brittle.
- Use the correct diameter. Over‑sizing stresses the feed mechanism; under‑sizing snaps easily.
- Avoid hard surfaces. Cutting against concrete, rocks, or metal fences shreds line instantly.
- Tap gently. A light bump releases just enough line; aggressive tapping wastes line and can damage the spring.
- Keep the spool clean. Grass buildup inside the head creates drag and uneven feed.
- Rotate the spool periodically. If one channel wears faster, swap the lines to even out wear.
- Choose reinforced line for tough jobs. Co‑polymer or titanium‑coated lines resist abrasion better than plain nylon.
Common Mistakes and How to Avoid Them
One frequent error is winding both lines in the same direction. The spool’s arrows exist for a reason—ignoring them causes the line to feed backward, leading to jams. Another mistake is over‑filling the channels. Leaving no clearance prevents the line from expanding under centrifugal force, which can crack the spool flange. Using mismatched diameters (e.g., 0.080 in on one side, 0.095 in on the other) creates an imbalance that vibrates the head and wears bearings prematurely. Forgetting to secure the line ends in the retaining notches lets the line slip out during the first spin. Finally, neglecting to clean the eyelets allows debris to act like sandpaper, cutting the line from the inside. Follow the step‑by‑step guide, double‑check arrow directions, and keep the spool clean to avoid these pitfalls.
Troubleshooting Feeding Issues
If the line does not advance when you tap the head, first verify that the spool rotates freely. Remove the spool and spin it by hand; any binding indicates a bent shaft or debris in the housing. Next, check that the line ends are properly seated in the retaining notches. A loose end will not catch the feed pawl. For automatic feed heads, ensure the line is threaded through the feed slots exactly as shown in the manual—missing a slot prevents the centrifugal mechanism from gripping the line. If the line feeds but immediately snaps, the diameter may be too small for the engine’s RPM, or the line may be old and brittle. Replace with fresh, correctly sized line. Uneven line length after feeding usually means one channel was wound tighter than the other; rewind both channels with equal tension.
Maintenance After Rewinding
After a successful rewind, run the trimmer at low speed for a few seconds to let the lines seat themselves. Inspect the head for wobble; a slight wobble is normal, but excessive vibration suggests a bent shaft or damaged spool. Lubricate the spool’s spring and drive tabs with a light machine oil if the manufacturer recommends it—this reduces friction and prolongs the spring’s life. Clean the air filter (gas models) or check battery contacts (cordless) to ensure the engine delivers consistent power, which in turn provides steady line feed. Store the trimmer with the head facing up to prevent line deformation from gravity. Periodically check the line length during long jobs; a quick visual check avoids unexpected run‑out.
Frequently Asked Questions
How often should I rewind my double string weed eater?
Rewind whenever the line length drops below the manufacturer’s minimum (usually 2–3 in). For average residential use, this occurs every 30–45 minutes of continuous cutting.
Can I use a single line in a double‑line spool?
Technically you can, but the head will be unbalanced, causing vibration and uneven wear. It is best to load two lines of the same diameter and type.
What happens if I wind the line opposite to the arrow?
The line will feed backward, jam the feed mechanism, and may damage the spool or the trimmer’s drive shaft.
Is there a maximum line length I should load?
Yes. Most spools have a fill line indicator. Over‑filling prevents the line from expanding under centrifugal force and can crack the spool flange.
Why does my line keep breaking near the eyelet?
Sharp or burred eyelets cut the line. Inspect the eyelets for damage and smooth them with a fine file or replace the spool if necessary.
Can I mix different line shapes (e.g., round and square) on the same spool?
Mixing shapes creates uneven drag and feeding. Use the same shape and diameter for both channels.
Do I need to replace the spool spring when I rewind?
Only if the spring shows signs of fatigue—loss of tension, rust, or deformation. A healthy spring can last many rewinds.
Conclusion
Mastering the art of winding a double string weed eater ensures your trimmer runs smoothly, cuts efficiently, and lasts longer. By understanding the type of head you have, selecting the appropriate line diameter and material, and following the precise winding arrows, you eliminate the most common sources of frustration—jams, uneven feed, and premature line breakage. The step‑by‑step process outlined above, combined with the practical tips and troubleshooting advice, gives you a complete toolkit for maintaining a reliable cutting edge all season long. Remember to clean the spool regularly, store line properly, and inspect the head after each rewind. With these habits in place, you’ll spend less time fiddling with line and more time enjoying a neatly trimmed lawn.