At some point, you will need to replace the mowing line, cutting head or blade on your grass trimmer or brush cutter. This guide explains how to do it safely and correctly.
How to replace a grass trimmer metal cutting tool
1. Switch off the grass trimmer or brush cutter. If you are using a petrol model, remove the spark plug. For cordless tools, remove the battery or disconnect the connecting cable.
2. Check that the correct deflector approved for the blade is fitted. Turn the grass trimmer upside down.
3. Insert a lock pin or Allen key into the hole in the gearbox. Turn the shaft until the pin clicks into place and locks the shaft.
4. Loosen the nut by turning it clockwise. Remove the blade and fastening components from the gearbox, but leave the thrust plate in place.
5. Fit the new blade onto the thrust plate. Make sure the collar of the thrust plate fits into the bore of the metal cutting tool.
6. Fit the thrust washer and rider plate onto the shaft.
7. Tighten the nut by turning it anti-clockwise with a combination socket tool. Replace any nut with damaged threads. Remove the lock pin or Allen key to release the shaft.
How to replace a grass trimmer head
1. Switch off the trimmer. If you are using a petrol model, remove the spark plug. For cordless tools, remove the battery or disconnect the connecting cable.
2. Check that the deflector is approved for the grass trimmer. Hold the tool so the spool faces upwards.
3. Insert a lock pin or Allen key into the hole in the gearbox. Turn the shaft until it locks in place.
4. Turn the grass trimmer head clockwise to loosen and remove it.
5. Screw the new mowing head on by turning it anti-clockwise until it engages with the shaft.
6. Tighten the mowing head while the shaft is locked. Remove the lock pin or Allen key.
Recommended products
AutoCut C 26-2 mowing head. Practical two-line mowing head for brush cutters.
GrassCut 230-2 / 260-2 grass-cutting blade. Cutting blades for dry and tough grass.
Important notes
Different cutting tools require different fitting steps. Always make sure the approved deflector for your replacement trimmer head or blade is fitted.
You can find the correct deflector and mounting details in the operating instructions of your brush cutter.
Summary: fitting a STIHL trimmer head or blade
- Wear suitable protective clothing and follow the steps in your operating instructions.
- Make sure the line spool faces upwards and the approved deflector is fitted.
- Lock the shaft using a lock pin or Allen key.
- To replace a mowing head, fit the new head and tighten it while the shaft is locked.
- To replace a metal blade, place it on the thrust plate, fit the thrust washer and rider plate, then tighten the nut.
- Remove the locking tool and release the shaft.
This article is based on content originally published by STIHL. The original version can be found here. Content used with permission.
