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Bulb Planters

  
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Bulb Planter

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Edge Angle

I recommend sharpening the outside perimeter of the digging edge. This is much easier and safer than trying to sharpen the inside edge.

Cautionary Note: It is best to not have a very sharp edge on this. As the sides of the cone taper out towards from the bottom to the top, it is common to push the dirt out from the bottom when using this tool. If it is too sharp, you might cut your hand when using this tool.

When the flower blooms, the bees come uninvited.

Ramakrisna

A 6" smooth cut machinist’s hand file is useful to carry in your gardening tools box. Use it to resharpen the bulb planter as needed throughout the gardening activity.

General Guidelines

Type

 α

Sharp
ness

Notes
Step-Upon 45°
3

This angle will make the tool easier to use, and the digging edge will last longer than if sharpened to a more acute angle.

Hand-held 35°
3

This is an option for this tool when working loose soil (i.e., soil which does not need as great a weight to push the tool into the soil). It could be as low as 30°; however that is not usually necessary and will cause the digging edge to lose its sharpeness sooner.

The more acute angle (45°) works well as an overall angle for the leading edge. It gives an edge which is less likely to be damaged if encountering rocks or other hard items in the soil.

Notes & Comments

Shaping the edge

New bulb planters I have purchased have an angle (α) of 90°. Therefore, initial shaping of the edge is to be expected.

If you 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

Use a machinist’s hand file.

  1. Start with a 12-14" bastard file (as necessary).
  2. Next, continue with a 8-10" medium (or second) cut file.
  3. Finish with a 6" smooth cut file, then use this file to remove the burr.
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Example icon

Sharpness Scale

Sharpness scales (as shown in the grey icon to the right) are used to indicate the recommended sharpness for the blades noted above. You can click on any of the icons showing the sharpness scale and be redirected to the page describing this more. Lower numbers are duller; higher numbers sharper.

These are general recommendations; you will need to use your own judgment, based on the knive’s intended purpose.

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