String-line trimmers make cutting grass easy in places a mower can't go. Using them wears down the cutting lines, though, and so the trimmers hold spools of extra line inside the cutting heads. When your cutting line gets too short, the trimmer feeds out new string automatically or when you gently bump the trimmer head on the ground (depending on which type of trimmer you have). Eventually, though, you're going to run out of string completely. When that happens, simply follow these five easy steps to replace the cutting line in your string-line trimmer.

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1) Stop the trimmer

Make sure the trimmer is switched off and that the cutting head has stopped spinning. Give the gearbox (if your trimmer has one) a chance to cool down before you move on to the next step.

2) Release the spool

The part of the cutting head that you're going to wrap the new line around is called the spool or reel. Different trimmer models offer different ways to access the spool. For some trimmers, you unscrew the “bump nob” from the cutting head and then remove the spool. For others, you'll need to unscrew a retaining ring or press on tabs that hold the spool housing in place. Be careful not to lose the spring inside the spool housing.

3) Cut string

For some trimmers, you can purchase pre-wound spools so you don't have to wind the string yourself. If your trimmer doesn't support this or you want to save some money, you'll have to wind the string yourself.

Make sure you purchase the right type of string for your trimmer. Then cut one or two strings to the recommended length, usually between 10 and 25 feet. Your owner's manual will tell you what type of string to us and how long to cut it.

4) Wind the string

Trimmers either have one spool and one line, one spool that's wound with two lines, or two spools stacked on each other that each have their own line. Your spool will have retaining notches to hold the line(s) in place when you start winding. There are also notches or slots on the top of the spool to hold the line(s) when you're done winding.

Start with your line or lines in the retaining notch. If your trimmer head has two spools, start with the spool closest to the holding slot notches. Once the end of the line is secured in the retaining notch, follow the arrows on the bottom of the spool that show which way to wind the line. Wind the line firmly and evenly until you have 5 inches of unwound line, then secure the line(s) in the holding slot(s). Repeat with the second spool, if your trimmer has one, starting with the retaining notch opposite the one you used when winding the first string.

5) Replace loaded spool

The spool housing will have one or two “eyelets,” or line exit holes. Usually, you'll feed the ends of the line(s) through the eyelet(s) and then snap the spool in place. For some models, though, you'll replace the spool and then feed the string through the eyelets. Your owner's manual will be able to tell you which method to use.

If the spring inside the housing came out during step 2, put it back now. Then once you've put the spool back, replace the bump nob, retaining ring, or spool housing cover. Gently tug on the line or lines to take up any slack and engage the spool.


If you need to purchase trimmer line or get help figuring out what type of line to use in your trimmer, we've got you covered. Richardson Saw & Lawnmower carries a variety of lines and other trimmer parts and we'll be happy to help you find exactly what you need for your trimmer.