Surface finish on a cutting edge

Graphic with relation of edge thickness and width of sharpening bevel asymmetric edge

Edge Finishing

The way a knife's cutting edge is finished impacts both its sharpness and the overall cutting feel. Let’s explore these factors:

Cutting Feeling

A smoother edge finish creates less friction, allowing the blade to glide through food effortlessly, resulting in a smoother cutting experience.

Sharpness

There’s an ongoing debate in various forums about whether a finely polished, mirror-like edge is sharper than a coarser, toothier edge. The answer depends on your cutting technique: For push cutting, such as slicing vegetables straight down, a finely polished edge typically yields the best results. For a slicing motion, some users argue that a slightly toothier edge (though not too coarse) is more effective for gripping the food as you cut.

There are different methods of finishing (sharpening) the edge in mass production:

Dry finishing

This is the most common and cost-effective method, used primarily for Western knives. The blade is first sharpened on a belt, and then deburred/refined on a leather wheel.

Pros: Fast and inexpensive.

Cons: The belt produces a coarser finish, leading to more friction and a less smooth cutting feel. If too much heat is generated during sharpening (visible through flying sparks), it can overheat the edge, weakening the material and causing chipping or corrosion.

Wet finishing

Commonly used for Japanese knives, this process involves sharpening on water-cooled whetstones followed by refining on a leather wheel. This technique is also referred to as "Honbazuke," meaning "true cutting edge."

Pros: Produces a smooth, sharp edge with no risk of overheating

Cons: It’s more time-consuming and expensive.

Number of production steps

The number of steps required to create a cutting edge depends on several factors:

Thickness of the blade on the edge prior to sharpening
Targeted edge angle
Targeted smoothness of the edge

In general, the more material that needs to be removed from the edge and the smoother the surface finish desired, the more time and production steps are required for sharpening.

If the edge is too thick before sharpening, material must be removed in two stages: pre-sharpening with a lower grit belt or stone to reshape the edge, followed by fine-sharpening with a higher grit, and then deburring/refining on a leather wheel.

If the blade is thin from the start, you can skip the pre-sharpening step and move directly to fine-sharpening with a high-grit material to achieve the desired sharpness.

A wide bevel after the first sharpening step may require additional steps to refine the surface finish. If the bevel is small, the process can be completed in one step.

Therefore, the number of production steps in sharpening doesn’t necessarily reflect the quality of the sharpening process.

Width of sharpening bevel

When sharpening a knife, the edge angle must be wider than the angle at which the blade is ground, which naturally creates a bevel.

The width of this bevel is determined by two factors: the blade’s thickness and the edge angle.

A thicker blade will produce a wider bevel (as seen in pic. A vs B). The narrower the angle, the wider the bevel (compare the edges on the left side to those on the right side in the drawing). A wide bevel could indicate either a thick blade or a narrow edge angle. However, the best and sharpest knives typically feature an acute edge angle with little to no visible bevel, which indicates that the blade is very thin at the edge.