Tool Sharpening: Adam Toth
SBBK Aug 2024 Meeting
Sharpening Bonsai Tools:
Principle:
Only sharpen the beveled edge, not the flat face..
Quality blades have a single-bevel edge—lay it flat on the stone. Maintain pressure evenly across the blade—and use a lot of pressure. Firm pressure.
Push or pull across the stone
Keep a consistent angle, do not let it rock, and use the full stone
Should feel the burr created on the backside, verify—should feel the burr across the length of the blade. Apply some blade to blade pressure, and merely closing the scissors will remove the burr on both sides
Testing if sharp enough, test against one’s fingernail and it should bite in—if it glides then dull.
If the face is polished and cannot see where the stone is making contact, can use a Sharpie to darken the edge and then sharpen and verify that the edge is sharpened.
What is needed:
Sandpaper ~ 400 grit ceramic is the cheapest option, but only lasts a few uses. Should say “for metal use”. Good place to start. Should be water proof but does not really need to use water like a wet stone.
Wet stone—not his recommendation, unless you are using it also for knives and chisels.
Two types: soaking or splash. Old type is to soak all bubbles out (30 min); newer type is a “Splash and Go”—requiring no soaking.
Up to 1000 grit, and don’t go above that. Typically scissors sharpened to 400 grit. (e.g. cutting meat or a clean cut > 1000 grit). For bonsai you want some bite, so it does not slide on the leaf or branch.
But for grafting, a fine grit will make a cleaner scion cut.
Adam prefers diamond stone, with different grit on each side. e.g. Amazon ~$40, lasts a life time.
Diamond plate card (business card size) can be a useful size to use anywhere.
Use rubbing alcohol or a little water to reduce the grit or dust
Stropping for grafting knives only—30k grit
Does not recommend using rust erasers—only for getting sap off, but don’t use it against or touching the edge. It will dull a sharp tool. Don’t use on the flat part of the scissors.
Don’t worry if the hinge is loose or feels loose—don’t mess with it, if the blades are sharp it will cut
Depending on frequency of use, but reasonably once a month
Uses petroleum jelly (opposed to oil being messy) to prevent rust
Concave or Knob—same theory, sharpen the beveled edge (inside)—maintain the outside edge metal.
Refrain from sharpening the outside edge—or to maintain the curvature of the outside profile
Put stone on the edge of the table and short motions on the inside edge—or sandpaper
Knob cutters and such do not need to be as sharp as scissors—cutting wood.
Or use dremel grinding tips spinning—does not require the same pressure as it rotates quickly (pink)
Start slow speed, once confident then use less pressure with higher speed.
Can sharpen saws with a feather file.
