How to String a Dewalt 20v Weed Eater? Easy Stringing for 20V Model

Introduction

If you’ve ever been in the middle of tackling overgrown grass and weeds only to have your Dewalt 20V weed eater spool run out of string, you know how frustrating that delay can be. Unlike gas-powered models that require messy refueling, your cordless Dewalt 20V trimmer is designed for convenience, but that convenience relies on a properly strung line. Many users assume replacing the string is a complicated, time-consuming task, but the process is straightforward once you understand your model’s head design and have the right supplies on hand. Whether you’re a first-time Dewalt owner or a seasoned landscaper looking to refresh your maintenance skills, this guide will walk you through exactly How to String a Dewalt 20v Weed Eater? with clear, step-by-step instructions for both common head types, plus tips to extend the life of your line and avoid common mistakes. By the end of this article, you’ll be able to replace your trimmer line in 10 minutes or less, no professional help required.

• Introduction
• Understanding Your Dewalt 20V Weed Eater
• Signs You Need to Replace Your Weed Eater String
• Tools and Supplies Required for Stringing
• Step-by-Step: How to String a Dewalt 20V Weed Eater
• Pro Tips for Optimal Performance and String Longevity
• Common Stringing Errors to Avoid
• How to Select the Best Replacement String for Your Dewalt 20V
• Frequently Asked Questions
• Conclusion

Understanding Your Dewalt 20V Weed Eater

Before you start the stringing process, it’s helpful to have a basic understanding of your trimmer’s head design, as the process varies slightly depending on which model you own. Dewalt’s 20V weed eater line includes several models, but nearly all use one of two standard string head designs: bump-feed and fixed-line. Each design has its own advantages for different use cases, and knowing which one you have will ensure you follow the correct steps for How to String a Dewalt 20v Weed Eater? without damaging your tool.

The string head is the component at the bottom of the trimmer shaft that holds the cutting line, spins at high speeds to cut vegetation, and (for bump-feed models) automatically advances more line when you tap the head on the ground. The head is secured to the trimmer shaft with a retaining nut or quick-release mechanism, depending on your model, and most users can remove it in 30 seconds or less with no special tools. Other key parts include the line spool (the circular component that holds the wound string), the line outlet holes where the string extends from the head, and the locking mechanism that keeps the spool in place during operation.

Signs You Need to Replace Your Weed Eater String

Most users only notice they need to replace their trimmer line when it runs out entirely, but there are several earlier signs that indicate it’s time to restring your Dewalt 20V weed eater before it leaves you stranded mid-job. Catching these signs early will also prevent unnecessary wear on your trimmer’s motor and cutting components.

The most obvious sign is uneven cutting performance: if your trimmer is leaving patches of uncut grass or struggling to cut through weeds that it normally slices through easily, your line is likely worn down, frayed, or too short to extend fully from the head. Another common indicator is frequent line breakage, which often happens when the line is old, brittle, or has developed nicks from hitting rocks, sidewalks, or other hard surfaces. You may also notice that the line no longer advances automatically on bump-feed models, or that it retracts fully into the head when you try to trim, both of which signal that the remaining line is too short to use effectively. Finally, if you see visible fraying, splitting, or discoloration on the line, it’s time to replace it immediately to avoid breakage during operation.

Tools and Supplies Required for Stringing

One of the best parts of stringing a Dewalt 20V weed eater is that you don’t need any specialized tools or expensive supplies to get the job done. Most of what you need is likely already in your garage or toolbox, and replacement string is widely available at hardware stores, home improvement centers, and online retailers for a low cost.

First, you’ll need the correct replacement string for your model. Dewalt recommends using 0.080-inch diameter round or square string for most 20V trimmers, but you can check your owner’s manual for the exact specification for your specific model. You’ll also need a sharp utility knife or scissors to cut the string to the correct length, a clean flat workspace to lay out your parts, and optionally a pair of work gloves to protect your hands from sharp string edges. If your model uses a quick-release head mechanism, you won’t need any tools to remove the head, but older models may require a small wrench or Allen key to loosen the retaining nut. Finally, have a small brush or cloth on hand to clean out any grass clippings, dirt, or debris from the head before you install the new string, as built-up grime can cause the spool to jam or the line to advance improperly.

Step-by-Step: How to String a Dewalt 20V Weed Eater

The exact steps for stringing your Dewalt 20V weed eater will vary slightly depending on whether you have a bump-feed or fixed-line head, but the core process is the same for both: remove the head, remove the old spool, wind the new string onto the spool, reinsert the spool, and reattach the head to the trimmer. Below are detailed, model-agnostic steps for both head types, followed by tips to ensure the string feeds smoothly during operation.

Stringing a Bump-Feed Head

Bump-feed heads are the most common design for residential Dewalt 20V trimmers, and the stringing process takes 5 to 10 minutes for most users. Follow these steps carefully to ensure the line advances correctly when you bump the head during use.

1. Disconnect the battery and remove the string head. First, remove the 20V battery from the bottom of the trimmer to avoid accidental startup while you work. Locate the retaining nut or quick-release tab on the bottom of the string head, turn it counterclockwise (or press the tab, depending on your model) to release the head, then pull the head straight off the trimmer shaft. Set the head on a clean, flat surface.
2. Remove the old spool and clean the head. Most bump-feed heads have a small cover on the bottom that you can pry off with a flathead screwdriver to access the spool. Once the cover is removed, pull the old spool out of the head. Use a small brush or cloth to wipe away any grass clippings, dirt, or tangled string remnants from the head cavity, as built-up debris can prevent the new line from advancing smoothly.
3. Cut the new string to the correct length. Measure out 10 to 12 feet of replacement string (the exact length varies by model, so check your owner’s manual if you’re unsure). Cut the string cleanly with a utility knife or scissors to avoid frayed edges that can jam in the head.
4. Wind the string onto the spool. Insert one end of the string into the small anchor hole on the center of the spool, then pull the string through until 2 to 3 inches of excess is sticking out of the hole. Hold the spool in one hand and wind the string tightly and evenly around the spool in the direction of the arrow printed on the spool; winding in the wrong direction will prevent the line from advancing when you bump the head. Leave 4 to 5 inches of string hanging off the end of the spool when you’re done winding.
5. Reinsert the spool and thread the line. Slide the wound spool back into the head cavity, making sure the ends of the string stick out through the two line outlet holes on the sides of the head. Pull the ends of the string until they are equal length, then snap the bottom cover back into place. You should have 6 to 8 inches of line extending from each side of the head.
6. Reattach the head to the trimmer and test the feed. Slide the head back onto the trimmer shaft, turn the retaining nut clockwise (or snap the quick-release tab into place) to secure it, then reinsert the battery. Turn the trimmer on and let it run for a few seconds, then bump the head gently against a hard surface to test the automatic feed. If 2 to 3 inches of line advances each time you bump the head, the string is installed correctly. If the line does not advance, remove the head and check that you wound the string in the correct direction and that the ends are not tangled inside the head.

Stringing a Fixed-Line Head

Fixed-line heads are less common on residential Dewalt 20V trimmers but are popular for commercial use and heavy-duty trimming of thick brush and overgrown vegetation. Unlike bump-feed heads, fixed-line models require you to manually advance the line by pulling the end of the string, and the stringing process is slightly different. Follow these steps to string your fixed-line Dewalt 20V head correctly.

1. Disconnect the battery and remove the string head. As with the bump-feed model, start by removing the 20V battery from the trimmer to prevent accidental startup. Loosen the retaining nut or release the quick-release tab on the bottom of the head, then pull the head straight off the shaft and set it on a flat workspace.
2. Remove the old spool and clean the head. Fixed-line heads typically have a removable spool cover held in place by a small clip or screw. Remove the cover, pull out the old spool, and wipe away any debris, grass clippings, or tangled string from the head cavity to ensure smooth line operation.
3. Cut the new string to the correct length. For most fixed-line Dewalt 20V heads, you’ll need 12 to 15 feet of replacement string. Cut the string cleanly with a utility knife or scissors to avoid frayed edges that can cause jams or breakage during use.
4. Wind the string onto the spool. Insert one end of the string into the anchor hole on the center of the spool, then pull the string through until 2 inches of excess is sticking out. Wind the string tightly and evenly around the spool in the direction of the arrow printed on the spool, leaving 6 to 8 inches of string hanging off the end of the spool when you’re done. Unlike bump-feed spools, fixed-line spools do not have line outlet holes; the string will be threaded directly through the head after the spool is inserted.
5. Reinsert the spool and thread the line. Slide the wound spool back into the head cavity, making sure the loose end of the string is accessible. Thread the loose end of the string through the small hole in the bottom of the head cover, then pull 8 to 10 inches of line out through the hole before snapping the cover back into place. This excess line will be used to manually advance the line when it wears down during use.
6. Reattach the head to the trimmer and test the line. Slide the head back onto the trimmer shaft, secure it with the retaining nut or quick-release tab, and reinsert the battery. Turn the trimmer on and let it run for a few seconds, then pull the loose end of the line firmly to test the manual advance function. If the line extends smoothly without jamming, the string is installed correctly. If the line sticks or does not advance, remove the head and check that the string is wound tightly and evenly on the spool, and that it is not tangled inside the head cavity.

Pro Tips for Optimal Performance and String Longevity

Once you’ve mastered the basic process of How to String a Dewalt 20v Weed Eater?, you can use these pro tips to extend the life of your string, improve cutting performance, and reduce the frequency of restringing. These small adjustments take almost no extra time but will make a big difference in how your trimmer performs over time.

• Pre-soak new string in water for 24 hours before installation. This may sound counterintuitive, but soaking nylon string in water before winding it onto the spool makes it more flexible and resistant to breakage, especially in hot, dry conditions where dry string becomes brittle and snaps easily.
• Wind the string tightly and evenly on the spool. Loose, uneven winding is one of the most common causes of jamming and poor line feed. As you wind the string, pull it taut with one hand to ensure each layer sits flat against the previous layer, with no gaps or overlapping loops.
• Trim the ends of the string at an angle after installation. Cutting the ends of the string to a sharp, pointed angle (instead of a straight cut) reduces drag as the line spins through the air, improves cutting efficiency, and reduces the chance of the ends fraying or catching on vegetation during use.
• Store replacement string in a cool, dry place. Exposure to direct sunlight, extreme heat, or moisture will degrade nylon string over time, making it brittle and prone to breakage. Keep spare string in a sealed plastic bag or container in your garage or shed to extend its shelf life.
• Clean the string head after every 5 to 10 hours of use. Built-up grass clippings, dirt, and sap can jam the spool and prevent the line from advancing correctly. Wipe out the head cavity with a dry cloth after each use, and use a small brush to remove any tangled string remnants.

Common Stringing Errors to Avoid

Even experienced users make mistakes when stringing their weed eater, and these errors can lead to poor performance, frequent line breakage, or even damage to your Dewalt 20V trimmer. Avoid these common pitfalls to ensure your stringing job lasts as long as possible.

First, never wind the string in the wrong direction. Almost all spools have a directional arrow printed on them indicating which way to wind the line; winding in the opposite direction will prevent the line from advancing correctly on bump-feed heads, and can cause the line to tangle or jam inside the head. Second, avoid using string that is the wrong diameter for your model. Using string that is too thick will jam the head and put excess strain on the trimmer motor, while string that is too thin will break easily and may not advance correctly. Stick to the 0.080-inch diameter recommended by Dewalt for most 20V models unless your owner’s manual specifies a different size.

Third, don’t leave too much or too little line extending from the head after installation. For bump-feed heads, 6 to 8 inches of line per side is ideal; too much line causes excess drag and reduces cutting efficiency, while too little line retracts fully into the head after a few minutes of use and will not advance when you bump it. For fixed-line heads, leave 8 to 10 inches of excess line hanging out of the head to allow for manual advancement as the line wears down. Finally, never force the spool into the head cavity if it doesn’t slide in easily. Forcing the spool can damage the locking mechanism or warp the spool, leading to jamming and poor performance. If the spool doesn’t fit, check that you wound the string evenly and that there is no debris blocking the cavity.

How to Select the Best Replacement String for Your Dewalt 20V

Not all weed eater string is created equal, and choosing the right type for your Dewalt 20V trimmer will have a major impact on cutting performance, string longevity, and ease of use. The two most important factors to consider are the string’s cross-sectional shape and its material composition. Below is a comparison of the most common string types to help you select the best option for your needs.

For most residential users, standard round nylon string is more than sufficient for weekly lawn maintenance. If you frequently trim thick weeds, overgrown areas, or small saplings, square or serrated string will provide cleaner cuts and last longer between replacements. Always stick to the diameter recommended by Dewalt for your specific model to avoid jamming or motor strain. Avoid using metal or plastic string, as these can damage your trimmer’s head and motor and are not designed for use with 20V Dewalt models.

Frequently Asked Questions

How often should I replace my Dewalt 20V weed eater string?

The frequency of string replacement depends on how often you use your trimmer and the conditions you use it in. For light residential use (1 to 2 hours per week), you’ll typically need to replace the string every 1 to 2 months. For heavy-duty commercial use or frequent trimming of thick, woody vegetation, replacement is needed every 1 to 2 weeks. You can extend string life by pre-soaking it in water before installation, avoiding contact with hard surfaces like concrete and rocks, and cleaning the head regularly to remove debris that causes fraying.

Why does my string keep breaking while trimming?

Frequent string breakage is almost always caused by one of three issues: incorrect string diameter, loose winding on the spool, or hitting hard surfaces while trimming. First, confirm you are using 0.080-inch diameter string as recommended for your model; string that is too thin breaks easily, while string that is too thick strains the head and causes breakage. Second, wind the string tightly and evenly on the spool; loose winding causes tangling and jams that lead to breakage. Finally, avoid hitting rocks, sidewalks, fence posts, and other hard surfaces while trimming, as these nick and fray the string, making it prone to breakage.

Can I string my Dewalt 20V weed eater without removing the head?

Some newer Dewalt 20V models feature a quick-access spool design that allows you to replace the string without removing the entire head from the trimmer shaft. To check if your model has this feature, look for a small release tab on the side of the head that, when pressed, allows you to pull the spool out directly without unscrewing the head. If your model does not have this feature, you will need to remove the entire head from the shaft to access the spool. Check your owner’s manual for specific instructions for your model to avoid damaging the head or shaft during the stringing process.

Conclusion

Stringing your Dewalt 20V weed eater is a simple, low-cost maintenance task you can complete in 10 minutes or less with the right tools and instructions. Whether you have a bump-feed head for residential use or a fixed-line head for heavy-duty work, following the correct steps for your model ensures the line advances smoothly, cuts cleanly, and lasts as long as possible between replacements. By recognizing signs you need to replace your string, using the correct replacement string for your model, and avoiding common mistakes like winding the line in the wrong direction or using the wrong diameter, you can keep your trimmer performing at its best for years. The next time your line runs out mid-job, you’ll know exactly How to String a Dewalt 20v Weed Eater? without needing a repair shop or replacement part. With regular maintenance and proper stringing technique, your Dewalt 20V trimmer will tackle even the toughest overgrown areas with ease.