How to Sharpen Bypass Loppers

Overview

Sharp garden tools are not only easier to use, but much better for the plants they're cutting. Sharp blades make tidy cuts, whereas dull blades tend to tear and crush stems and branches. Because the sharpening process also involves cleaning of the cutting surfaces, well-maintained bypass loppers also tend to transmit fewer plant diseases. Sharpen hand pruners and bypass loppers at least once a year.

Disassembling and Cleaning Bypass Loppers

Step 1

Loosen the nut from the central fastening bolt by twisting in a counter-clockwise direction with an appropriately sized wrench. Spray with a lubricant, such as WD-40, to ease a stubborn bolt.

Step 2

Separate the cutting blade from the hook side by completely unscrewing the nut from the bolt. Pull the cutting blade side away from the hook side (the non-cutting edge).

Step 3

Use a toothbrush to clean away particles in the groove of the hook-side of the loppers.

Step 4

Wipe both sides of the loppers clean with a dry cloth.

Step 5

Finish the cleaning with a final polish of steel wool.

Sharpening the Bypass Loppers

Step 1

Hold the handle of the cutting blade section against a flat work surface so that the blade extends past the edge of the work surface. This allows a wide range of movement to work around the blade.

Step 2

Set the edge of the sharpening stone against the cutting edge and file the blade from the base of the lopper blade toward the tip. Filing motions should always be down and away from the body.

Step 3

Maintain a consistent angle with the sharpening stone. Altering the angle will round the cutting edge of the blade and make it dull rather than sharp. Run the sharpening stone down the blade until you have achieved a satisfactory edge.

Step 4

Make several passes with the sharpening stone along the reverse side of the cutting blade to remove any metal burrs or rough edges.

Step 5

Reassemble loppers by sliding bolt through the cutter section, followed by the hook section. Lightly tighten the nut over the bolt using your fingers. To align the cutting edge with the hook section, set the two sections together and tighten the bolt firmly with the wrench. Continue by unscrewing the bolt gradually, by quarter turns, until the loppers just open. Lopper blades should then grind slightly when pushed closed; this is a sign of a proper alignment.

Things You'll Need

  • Wrench
  • Lubricant
  • Steel wool
  • Toothbrush
  • Soft, clean cloth rag
  • Medium-grit diamond sharpening stone

References

  • "Garden Gate Magazine": Maintaining Bypass Pruners [Videos]
  • Blue and White Crew: How to Sharpen Bypass Loppers
  • University of Wisconsin: Pruning Woody Plants
Keywords: sharpening bypass loppers, bypass lopper maintenance, bypass lopper care

About this Author

Michelle Z. Donahue lives in Washington, D.C., and has worked there as a journalist since 2001, when she graduated from Vanderbilt University with a B.A. in English. She first covered politics as a reporter for the weekly Fairfax Times newspaper, then for the daily newswire Canadian Economic Press, where she reported from the U.S. Treasury. Donahue is currently a freelance writer.