Ideally, you shouldn’t wait until the blades are showing signs of serious wear before sharpening them. The blades should be sharpened regularly after about every 50 hours of operation to maintain cutting performance.
When cutting back branches in hedges, sap and resin residue gathers on the hedge trimmer blades. Remove any dirt before sharpening, otherwise you could damage the file and the stone.
As a rule of thumb, only sharpen the cutting edge. Ensure that the file does not come into contact with the integrated cut protection or, in the case of professional hedge trimmers, the orange plastic cut protection.
1. Sharpen using a flat file
To ensure long-lasting cutting performance, follow these two steps. First of all, a flat file can be used.
Make sure that the upper and lower blades come to rest at the same position. This simplifies the filing process.
Always file in the direction of the cutting edge. This is how the flat file is designed to work and guarantees an optimum cutting edge. Try to maintain the specified sharpening angle. This can be found your equipment’s instruction manual under “Specifications”.
Only sharpen the blade downwards in the direction of the cutting edge. Ensure the file is not in contact with the blade when pulling back upwards, or the blade will become blunt.
Above all, make sure you do not file away too much of the blade. The wear threshold is 5mm. If you file away more than this, the material may lose strength.
The hedge trimmer’s performance will also be negatively affected if you vary the force when filing, as this will lead to blades of different lengths.
2. Remove the burr with a sharpening stone
For the second step, remove the burr from the bottom of the blade using a sharpening stone.
After the blade has been sharpened, the swarf should be removed. We also recommend that you spray the blades with resin-free spray or STIHL Multispray to prevent the steel blades from rusting.
Our video guide shows you how to sharpen your hedge trimmer step-by-step:
However, the best bet is to take your hedge trimmer blades to a STIHL specialised retailer for sharpening. They use sharpening machines, which guarantee the optimum sharpening angle at all times and ensure that not too much material is filed off. You can locate your nearest specialised retailer on our website: www.stihl.com/local-stihl-representative.aspx