How to Put a String on a Weed Eater

Weed eaters (also called string trimmers, depending on your region) are effective for cutting grass and weeds that lawnmowers cannot reach, such as long grass. But before using one, you must understand how to thread its string.

Following these steps will make using your weed eater easier, although your user manual may contain slight differences.

Winding the String

As the string in a weed eater is responsible for cutting through grass and weeds, its wear must be replaced periodically to remain effective. Installing a new line may appear daunting at first, but the process is fairly simple.

Once the weed eater is clear of debris and string, remove any remaining material by unscrewing its cap and carefully cutting away any leftover wires. Finally, wind a new line onto its spool as directed by the arrows on its surface.

Alternatively, if your weed eater is a bump-feed model, tap its spool against a hard surface to start dispensing string. Or reattach the cap and press the button on its head to dispense the line from its storage tube automatically. Or consider switching over to an automatic feed weed eater instead!

Threading the String Through the Shaft

Attaching a new string to your weed eater (aka grass trimmer or weed whacker) may differ slightly depending on its make and model; typically, following instructions in its user manual should do the trick.

Before beginning, be certain you’re using the appropriate size string for your weed eater. A too large string could get caught in its mechanism, while a too little string will fail to cut properly.

Many weed eaters only fit certain string thicknesses; using thicker string may hinder its performance or damage your lawn care equipment.

Threading the String Through the Bump Head

Many weed eaters (string trimmers or weed whackers) feature manually activated bump heads that release string when you push against the ground, unlike their auto-feed counterparts that feature removable spools for easier restringing. These weed eaters don’t usually offer removable spools so that resetting can take more effort.

Start by unthreading any old string hanging from the head of your weed eater, then adjust its bump head so any arrow marks align correctly. Reattach its cap and feed your new string through its opening on the bump head until fully installed.

Keep the string that suits your weed eater by selecting one with the appropriate gauge and gauge size. Referring to your user manual or reading labels can help determine this information; using an incorrect string could cause it to malfunction or even break. Twisted squares and serrated string shapes work better when selecting specific tasks.

Reattaching the Spool Cap

Some weed eaters feature an auto-feed mechanism that enables you to attach pre-wound string spools without taking the head off or using a ratcheting tool. If this is your weed eater’s case, line up its holes and distribute the string evenly until about 10 feet of each end sticks out of its respective spool unit.

Once the new string is securely in place, reattach its spool cap. As this may differ depending on your camera model, look out for a notch or hole in the spool, as this will keep it from moving while winding the string.

Some models feature arrows outside their spool to indicate how to wind the string, so follow these arrows closely or your string may need to dispense properly.


In conclusion, putting a string on a weed eater is a simple yet crucial task for effective lawn maintenance. Following the right steps ensures optimal performance and longevity of your equipment.

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