Introduction
Restringing a Dewalt 20V weed eater is a routine maintenance task that keeps the trimmer cutting cleanly and extends the life of the tool. Whether you are a homeowner tackling a weekend yard project or a professional landscaper who relies on cordless power, knowing how to string Dewalt 20v weed eater correctly saves time and prevents frustration. This guide walks you through every stage, from identifying the right spool and line to loading the trimmer head safely and testing the result. You will also learn how to choose the best line for your specific cutting conditions, avoid common pitfalls, and keep the trimmer running smoothly after each restring.
Table of Contents
- Understanding Your Dewalt 20V Weed Eater
- Tools and Materials Needed
- Safety Precautions
- Step-by-Step Guide to Stringing the Trimmer
- Choosing the Right Trimmer Line
- Comparison Table: Line Types
- Tips for Longer Line Life
- Common Mistakes and How to Avoid Them
- Maintenance After Restringing
- Troubleshooting Common Issues
- Frequently Asked Questions
- Conclusion
Understanding Your Dewalt 20V Weed Eater
Model Variations
Dewalt offers several 20V MAX string trimmer models, including the DCST920, DCST970, and the newer DCST990. While the overall design is similar, the spool housing and line feed mechanism can differ slightly. Check the model number on the motor housing or the battery compartment to confirm which spool style you have before purchasing replacement line.
Spool Types
Most Dewalt 20V trimmers use a bump‑feed spool that advances line when the head is tapped on the ground. Some newer models feature a fixed‑line head that accepts pre‑cut lengths. Identifying whether you have a bump‑feed or fixed‑line head determines the loading technique you will follow in the step‑by‑step section.
Tools and Materials Needed
- Replacement trimmer line (typically .080‑inch or .095‑inch diameter)
- Scissors or a sharp utility knife for cutting line
- Clean rag or shop towel
- Protective gloves
- Safety glasses
- Optional: small flat‑head screwdriver for stubborn spool caps
Having everything within reach before you start prevents interruptions and reduces the chance of dropping small parts into the grass.
Safety Precautions
Always remove the battery pack before working on the trimmer head. A sudden trigger pull can spin the head at high speed and cause serious injury. Wear safety glasses to protect your eyes from debris that may be released when the spool is opened. Gloves improve grip and protect your hands from sharp line ends. Work on a stable, flat surface and keep children and pets away from the area.
Step-by-Step Guide to Stringing the Trimmer
Follow these ordered steps to restring your Dewalt 20V weed eater correctly. The process is the same for most bump‑feed models; fixed‑line heads only differ in the final loading step.
- Remove the battery. Press the release latch and slide the battery off the tool. This eliminates any chance of accidental startup.
- Detach the spool housing. Hold the trimmer head firmly and turn the spool cap counter‑clockwise until it releases. Some models have a push‑button release; press it while turning.
- Take out the old spool. Pull the spool straight out. If line remains, unwind it and discard. Inspect the spool for cracks or excessive wear; replace the spool if damaged.
- Clean the spool and housing. Wipe away grass clippings, dust, and old line fragments with a clean rag. A clean surface ensures smooth line feeding.
- Cut the new line to length. Most Dewalt spools require two equal lengths of line, each about 10‑12 feet. Measure and cut with scissors or a utility knife. Cutting a little longer is better; you can trim excess later.
- Load the line onto the spool. Locate the anchor holes or notches on the spool. Insert one end of each line into the corresponding anchor, then wind the line neatly in the direction indicated by the arrow on the spool. Keep tension even to prevent crossing.
- Leave a short tail. After winding, leave roughly 6‑8 inches of line protruding from each side of the spool. These tails will feed through the eyelets when the spool is reinstalled.
- Reinstall the spool. Align the spool with the housing, feed the tails through the eyelets, and press the spool into place. Replace the spool cap and turn clockwise until it clicks or locks.
- Reattach the battery. Slide the battery back onto the tool until it locks.
- Test the trimmer. Start the motor at low speed, then tap the head lightly on the ground to advance line. Verify that line feeds smoothly and cuts cleanly.
Choosing the Right Trimmer Line
Diameter and Shape
Line diameter determines cutting power and durability. The .080‑inch line is standard for light residential use, while .095‑inch handles thicker weeds and light brush. Shaped lines such as twisted, serrated, or star‑shaped profiles cut more aggressively and reduce drag, but they can wear faster on hard surfaces.
Material Composition
Most lines are nylon copolymer, offering a balance of flexibility and strength. Premium lines may include a co‑extruded core for added tensile strength or a coating that reduces friction. Choose a line rated for the temperature range you work in; extreme heat can soften standard nylon.
Comparison Table: Line Types
| Line Type | Diameter | Best For | Pros | Cons |
|---|---|---|---|---|
| Round Nylon | .080‑.095 in | General grass trimming | Low cost, widely available | Wears quickly on tough weeds |
| Twisted / Serrated | .080‑.095 in | Thick weeds, light brush | Cleaner cut, less drag | Higher price, faster wear on concrete |
| Star / Multi‑Edge | .095‑.105 in | Heavy brush, small saplings | Aggressive cutting, long life | Can overload motor on light trimmers |
Tips for Longer Line Life
- Keep the trimmer head at a slight angle to the ground; dragging the head flat increases friction.
- Avoid cutting against hard surfaces such as sidewalks, curbs, or rocks.
- Use the correct line diameter for the model; oversized line stresses the motor and feeds poorly.
- Store spare line in a cool, dry place to prevent UV degradation.
- Periodically clean the spool housing to remove grass buildup that can impede line advance.
Common Mistakes and How to Avoid Them
- Over‑winding the spool. Too much line causes binding. Follow the manufacturer’s recommended length.
- Crossing the two line strands. Crossed lines jam the feed mechanism. Wind each strand in its own channel.
- Using the wrong line diameter. Undersized line breaks often; oversized line stalls the motor. Check the manual.
- Forgetting to remove the battery. This is a safety hazard and can damage the tool if the trigger is accidentally engaged.
- Not seating the spool cap fully. A loose cap lets the spool wobble, leading to uneven feed.
Maintenance After Restringing
After you have successfully restrung the trimmer, run it for a minute at low speed to let the line settle. Inspect the head for vibration or unusual noise. Clean the air vents on the motor housing to maintain cooling efficiency. Lubricate the spool shaft lightly with a silicone‑based spray if the manufacturer recommends it. Store the tool with the battery removed and the head covered to keep debris out.
Troubleshooting Common Issues
- Line does not advance. Verify that the spool cap is tight, the line is not tangled, and the bump‑feed mechanism moves freely.
- Line breaks immediately. Check for sharp edges on the eyelets, use a thicker line, or reduce throttle when hitting dense material.
- Excessive vibration. Ensure the spool is seated evenly and the line lengths are balanced.
- Motor stalls under load. Confirm the battery is fully charged and the line diameter matches the tool’s rating.
Frequently Asked Questions
How often should I restring my Dewalt 20V weed eater?
Restring whenever the line becomes too short to cut effectively, typically after 30‑60 minutes of heavy use. Frequent users may restring weekly.
Can I use any brand of trimmer line?
Yes, as long as the diameter and shape match the specifications in the owner’s manual. Using incompatible line can void the warranty.
Why does the line keep jamming?
Jamming is usually caused by crossed strands, over‑winding, or debris in the spool housing. Clean the housing and reload carefully.
Is it okay to use pre‑cut line lengths?
Pre‑cut lengths work with fixed‑line heads but are not recommended for bump‑feed spools, which require continuous line for proper feeding.
How do I know which direction to wind the line?
Look for an arrow molded on the spool body; wind in the direction the arrow points. If no arrow is present, wind clockwise when viewing the spool from the top.
Conclusion
Mastering how to string Dewalt 20v weed eater ensures your trimmer stays ready for any yard task. By understanding your specific model, gathering the right tools, following the step‑by‑step loading process, and selecting the appropriate line, you minimize downtime and maximize cutting performance. Regular maintenance, awareness of common mistakes, and quick troubleshooting keep the tool running smoothly season after season. With these practices in place, you can approach each trimming job confidently, knowing the line will feed reliably and cut cleanly every time.