Japanese Folding Saw for Gardening  

The Japanese folding saw used for gardening is not one I would try to re-sharpen for many reasons.

1

Blade's teeth, viewed from the side

The Japanese saw blade has a tooth shape which is quite complex. The blade will typically have multiple angles cut into each individual tooth, and these can change across the saw's length.

A 3rd or 4th angle in a single tooth is not uncommon.

 

2

Silky Blade, viewed from the end

The blade on the Silky brand of Japanese gardening saws have a shape where the sides are not straight from base to top. As depicted in the picture to the right,

  • the center of the blade is thinner than the top, and
  • the cutting edge of the teeth (bottom in this picture) is wider than those two.

This helps make the saw work well, but it would make re-sharpening the blade more difficult.

Other brands may have the same style of shape.

3

Additionally, it is common for these saw blades to have impulse hardened teeth, making it virtually impossible to use a machinist's file to re-sharpen them. Even diamond cards will not work.

Impulse-Hardening

Silky in New Zealand have a YouTube video (see below) which discusses the difference between those blades which can be re-sharpened, vs those which cannot.

Saw blades which have this marking cannot be re-sharpened for all the reasons noted above.

This can also make the teeth brittle.


Gardening is an exercise in optimism. Sometimes, it is a triumph of hope over experience.

Marina Schinz

Don Williams at The Barn at White Run was successful using a diamond-shaped, aluminum oxide, “India” stone. Whilst most simply replace the blade, resharpening a blade is apparently possible.

 

Saw Sharpening Notes

Sharpening Angles for Silky Saw Blades
Image courtesy Silkystore (New Zealand)

Sharpenable

Saw blades with the marking shown to the left can be resharpened.

If you want to pursue sharpening this type of saw, these notes may be of help.

Key Note:If you do choose to sharpen these saws, be sure you also understand what the set needs to be. It is common for there to be no set; instead the changing width of the teeth accomplishes the same objective.

Feather-Edge File

When sharpening these saws, a feather-edge file is needed. Such files are quite thin and are able to fit into the small space between this saw's teeth.

 

 

Product Angle
A B C
Genki Temagari 500 27° 50° 50°
Hayauchi 21° 50° 50°
Hayate 33° 45° 40°
Ibuki 21° 50° 50°
Katanaboy 27° 50° 50°
Natanoko 27° 50° 55°
Sugoi 33° 45° 40°

The various angles for resharpenable Silky blades are shown in the table at the left. These correlate with the picture shown to the right.

General Guidance

The general guidance given is that the sharpener can file the ends of the teeth 2 or 3 times before the sides need to be filed. (In the picture to the right, the ends of the teeth are noted as ②, and the sides are noted as ①.)


Other vendors' saw blades will have similar measurements. Their tables will need to be consulted for the sharpening activity.

Notes & Comments


More Information

Videos & Presentations