Sharp shears make light work
Sharp shears are a necessity to avoid ripping those stems rather than slicing them neatly. It also decreases the muscular effort required to make the cut, saving your hands. Fortunately, keeping shears sharp as new is simple with the proper tools and technique.
For larger shears, such as grass or hedge shears, the technique is very similar to sharpening a rotary lawnmower blade. Clamp the shear into the jaws of a bench vice. Clean off any debris and oil lightly using a fine machine oil.
Then take a medium to fine file and apply a stroke from the centre to the edge at the same angle as the bevelled edge. Repeat a few times on each blade until all nicks are removed and the edge is sharp again.
An electric bench grinder can perform the job in seconds, provided it's done carefully. It's possible to ruin a pair of shears as quickly as you can sharpen them. Removing too much material will cause a gap between the blades, eliminating their cutting ability.
It's also important to clamp at the correct angle and to ensure that only short grinds are used. Building up too much heat in the metal will make it brittle. Proceed slowly and carefully, using the on-board tool clamp, and you can be done in a jiffy.
For smaller shears, clamp the tool in a bench vice and use a small, fine metal file on clean, oiled shears. Again, take care to keep the angle of the file the same as that of the bevel. Hand-assisting guides are available for those who need a little help. They're similar to those used for sharpening chainsaw chains.
For detail work, steel wool will help remove rust and small pits, as well as putting a very fine edge on the shears. Only file or work on the curved (bevelled) edge, not the flat edge unless absolutely necessary and always away from the body. It's important not to create a gap between the blades, since it's that clamping action that creates the shear force that cuts. Only work on the flat edge to remove burrs produced from forcing metal out past the edge.
File or polish in only one direction, moving from the vertex (the point or angle where the blades come together), out to the tips. Proceed lightly at first. It's always possible to take off more, but impossible to put it back.
Anvil shears require a slight modification of the technique. These shears have a single blade that hits a flat surface, like an anvil. The other type, the more common pruning shears are called bypass shears since the blades bypass one another in order to cut.
To sharpen an anvil pruner, simply clean and clamp as before. In this case, however, both sides of the blade need to be sharpened. Here again, though, it's important to keep the file at the same angle as the bevel of the blade and not to work too vigorously.
In some cases, it may be helpful to unscrew the shears, separating the two parts. That allows easy access to the innermost point, where the blades may be dullest. Clamp each part separately and proceed as described above.
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