Properly sharpen pruners & loppers

Features - Equipment

Sharpened tools not only save labor but are an important piece of the pruning puzzle. They also help keeping your plants healthy. Here's how to properly sharpen pruners and loppers.

April 26, 2011

Sharpened tools not only save labor but are an important piece of the pruning puzzle. Make sure your crew is properly sharpening pruners and loppers.

Stan Watson, technical director for Diamond Machining Technology (DMT), offers his expertise.

Sharp garden pruners and loppers have several advantages over dull ones. The biggest advantage is to the health of your plants. Sharp tools cut cleanly, minimizing the plant’s healing time. Sharpening also protects your investment—for both the tools and the plants.

The first step in sharpening any pruner or lopper is to remove any dried-on sap, grime and dirt from the blade.

For pruners or loppers, use a flat file or a hone. Holding the pruner or lopper handle that the blade is attached to in one hand, and standing under a fairly bright light, rotate the blade up slowly, starting with the flat backside of the pruner blade parallel to the floor. As you rotate the blade up slowly, look for a reflection of light back up to your eye from the cutting bevel and stop where the reflection is the brightest. You now will have the cutting bevel level. Hold the file or hone level and stroke into the cutting edge from the heel of the blade to the tip in one smooth stroke. This method ensures you will both accurately match the original bevel angle and, since you are stroking into the cutting edge, you will not roll up a burr on the backside of the blade.

For anvil pruners and loppers, hold the pruning tool with one hand with the cutting edge of the blade facing away from you. Use the same method described above to level the bevel and hold the file or hone parallel to the floor. Stroke away from the cutting edge from heel to tip ensuring that you remove an even amount of material from the entire bevel edge. Because you are stroking off or away from the bevel, you will likely roll up a burr on the opposite side, but that’s okay. Now rotate the pruners so that the cutting edge is facing you. Level the bevel again and you will see that now you will be stroking into the cutting edge and will therefore remove any burr you just created. One important difference to remember between sharpening anvil and bypass blades is removing an even amount of material from the anvil blade. Since it closes down on an anvil and doesn’t bypass it, any excess material you remove from one section of the blade as compared to another will leave you with a gap between the bevel edge and the anvil, and that will result in incomplete cuts.

To finish up, apply a small amount of lubricant to both sides of the blades and/or anvil. This serves two purposes; it keeps the joint lubricated and helps prevent the accumulation of dirt, sap and grime. You can also protect wooden-handled tools with linseed oil or a coat of varnish, and be sure to store your tools in a dry place.

Stan Watson is technical director at Diamond Machining Technology,