General Information on Sharpening

Typical Grinding Media Used
  • SB-250 Original Grindstone, graded course
  • DC-250 Diamond Wheel Course
  • 60 grit ProEdge Zirconium Belt
  • CBN wheel : 100-150 grit
  • Very friable grindstone : 100 - 180 grit
  • Sandpaper : <200 grit

Shaping the Tool - Knives are reshaped pretty rarely. Common reasons for reshaping include : when the knife has a broken point off the end (or other significant damage), and when the back needs to be ground down on a folding knife so that the point doesn't catch on the trousers.

Typical Grinding Media Used
  • SB-250 Black Grindstone, graded fine
  • DE-250 Diamond Wheel Extra Fine
  • DF-250 Diamond Wheel Fine
  • 120 grit ProEdge Zirconium Belt
  • Pedia ProEdge Diamond Belt
  • 600 grit ProEdge Trizact Belt
  • 1,200 grit ProEdge Trizact Belt
  • CBN wheel : 200+ grit

Sharpening the Tool - Knives should be resharpened often. And of course, the knife must be resharpened whenever the owner gets it back from their brother-in-law (who probably tried to open a paint can or carve concrete with it).

KnifeGrinders have well outlined sharpening procedures on their web site, and have basic routine described for Tool and high-end steels.

If you have time and are after strict experimental facts, read their lengthy research, "Edge Rolling in High Vanadium Knives Sharpened with Aluminium Oxide versus CBN/Diamond".

It is a common, but quite bad practice of drawing the newly sharpened knife edge through a piece of wood or some other media to “rip off” the remnants of the burr. When this is done, the ripped off metal builds up on the front of the slice, and you then drag the rest of the edge through this crud. This crud, together with breaking off of ledges of material along the edge, will roughen the edge and worsen sharpness.

The following scanning electron microscope (SEM) images show the burr on a knife in the 1st image, that was then “ripped off” by cutting cross-grain into a piece of redwood in the 2nd image – loss of the sharp edge is obvious.

Images courtesy Todd Simpson via Vadim Kraichuk of KnifeGrinders

Key take-away from these photos : don't skip the honing step.

Honing and Stropping
to remove the burr
Typical Grinding Media Used
  • SJ-250 Japanese Waterstone
  • 3,000 grit ProEdge Trizact Belt
  • Japanese Waterstone : 4,000+ grit

Honing the Tool - Some owners combine honing and stropping together; this can certainly be done on marking knives. But, for woodcarving knives, these are two separate steps.

KnifeGrinders have a great book about the value of, and process for, honing titled, Knife Deburring.

Note: When honing or stropping, the side to start on is the one where the grinding was last done. If you start on the other side, the burr will get ripped off and you can end up with an edge like above.

Typical Grinding Media Used
  • Leather honing wheel with a honing compound
  • Paper wheel with a honing compound or diamond honing paste
  • Leather strop (e.g., horse butt leather) with a honing compound
  • Medium density fibreboard (MDF) shaped for the tool's edge, and using a honing compound or diamond paste

Stropping the Tool - Some woodworkers choose not to strop their tools, whilst others do strop. There was a great debate on Fine Woodworking's podcast #178 about this. Bob Van Dyke advocated it whilst Mike Pekovich seemed to pooh pooh it.

My experience has been that stropping is especially useful when using the SJ-250 Japanese Waterstone for honing. I do not have finer stones (e.g., 12,000 grit Japanese waterstones), so stropping seems to cover that gap for me.