Secateurs, Bypass Loppers, & Pole Pruners  

Cutting Blades Coloured

 

Angles of Cutting Blades

Secateurs are also known as Bypass Pruners, Hand Pruners, and Pruning Shears. Bypass Loppers are sharpened using the same guidance as Secateurs. Additional information for sharpening Pole Pruners is in the comments section.

Angles are shown in the end views of the upper blade (red) and lower blade (blue).

The best tool in the garden is the knowledge of the gardener.

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A 6" smooth cut machinist’s hand file is useful to carry in your gardening tools box. Touching up the upper blade (red) may be needed to ensure you have clean cuts.

General Guidelines
Angle Recom. Notes
β1 20°

This angle is not terribly critical and probably does not need to be addressed. What I have observed is (generally):

β1 = β2 - 10°

A critical aspect when sharpening these tools is that the adjoining sides of the two cutters (the red and blue parts) must be coplanar.

 
Sides coplanar   Sides not coplanar
β2 30°

This angle can be as high as 35°, though that will make cutting the plant harder for thicker pieces (e.g., branches).

KJ-45 Projection is the distance the blade projects beyond the end of the KJ-45 jig, and assumes that the sharpener is using the bottom stop.

β3 n/a

This angle (i.e., the lower (blue) blade) could be as low as 80°; however it is not terribly critical. What is important is that the angle is sharp and not rounded over, and that the blade is not corruded with tree sap nor rust.

Pole pruners: be sure to look at this, especially on the first sharpening. Many lower quality tools need this to be re-shaped, making them work significantly better.

Notes & Comments

Information regarding Grindstones

Felco manufactures secateurs for many vendors. Consider following the guidelines noted below for Felco Hand Pruners.

Sharpening Notes for the Secateurs' Edges

Shaping the edge

New secateurs and bypass lopers I have purchased have not needed to be reshaped. However, they may need work if a nick is incurred in the blade.

A 12-14" bastard machinist’s hand file is often sufficient for reshaping the tool's cutting edge.

If you choose to use an angle grinder, consider using a 120 grit flap disc. A metal grinding wheel may be needed for large-scale shaping. In either case, be sure to not overheat the metal too much: it weakens the metal.

Sharpening the edge

For secateurs, I find that the Tormek works quite well, especially if the blade can be detached from the tool.

KJ-45 bottom stop

Tormek KJ-45 Jig Notes

When using the KJ-45, use the bottom stop (this is shown in the picture to the right, and is indicated using a red arrow). Using the bottom stop is necessary to achieve the sharpening angle for β2.

Tormek SVM-45 Jig Notes

When using the SVM-45, the collar pivot jig designed by CB (shown below) works best.

The collar pivot jig is needed to ensure the SVM-45's handle is held close to the blade, and is necessary to achieve the sharpening angle for β2. It also helps with swinging the blade across the grindstone, sharpening it across the curved blade's edge.

You can also use machinist’s hand files. Start with an 8-10" medium (or second) cut file, and finish with a 6" smooth cut file, then use this file to remove the burr.

Felco Hand Pruner Notes

The tools needed to remove the blade for sharpening it are:

The video below, Cleaning & Sharpening Felco Secateurs For The Gardening Season Ahead, may be useful for the disassembly & re-assembly of the secateurs.

Pole Pruner with Saw Blade

Pole Pruner Cutting Blades
Double Lever & Single Lever Pole Pruner

Pole Pruners

Pole pruners also need to be sharpened to work as expected. The two traditional types are shown in the picture at the bottom left.

The two blades are noted in red & blue in the picture to the left, and are sharpened as noted above. Also, as noted above, the sharpener must ensure the blades remain coplanar.

The video noted below, “Pole Pruner Maintenance”, is a good reference for the other maintenance activities, especially lubrication, needed to ensure long life of this tool.

If the pole has a saw blade attached as shown in the picture to the right, the saw blade is sharpened following the instructions for Hand Saws.

Pole Pruner Maintenance

If the pole pruner has not been maintained before (much less sharpened), you should plan to replace all the attachment screws. Also, if the parts have been bent (since the blade was dull), you will need to straighten everything out before re-assembly. A bench vise and a dead-blow mallet are useful for this.

Pole Pruner - Optional Configuration

There was a version of the pole pruner where a chisel blade is attached to the end in lieu of a saw blade. If you are sharpening the chisel blade, the recommended angles are noted in the table below.

  αPrimary Bevel 30°
  αMicro Bevel +5°

The use of a microbevel allows for fast resharpening / touch-up in the field.

More information about chisels is available at the chisels page.

More Information

Videos & Presentations

Web Sites