Single bevel knives - a guide on how we sharpen and repair them

Below are examples of single bevel Japanese knives serviced in our workshops.

There are two types of blade profile.

A double or single bevel blade profile.

How can you tell which is which?

This is relatively easy.

Double bevel knives are a general 'V' shape, meaning both sides of the blade descend down from the spine to the cutting edge at the same angle creating a 'V' shape.

This is by far the most common blade profile making up 99% of all knife models.

The second and more rarer blade profile is the single bevel blade.

The single bevel blade is often called a 'chisel edge' as one side of the knife will descend vertically from spine to cutting edge at no angle with the other side of the blade descending at an angle.

At Blade & butler we examine every knife we receive.

Genuine single bevel knives will always be sharpened on one side only, giving a true single beveled edge.

We administer a discreet 1- 5 mm secondary edge bevel to the bevelled side of the blade only. This is then polished and buffed to a super smooth finish.

Double beveled knives will will sharpened on both sides, correctly as the manufacturer intended.

The below image is of a true single bevel Global G-7 and Petty companion that passed through our workshops. Both blades have been reconditioned and polished with bevels created on one side only.

Below describes in detail how we service single bevel knives with chips in the cutting edge

When chips present in the cutting edge ( the 'Koba' in Japanese ) we grind out the chip until it is removed. We are then left with a square edge. We then regrind the primary bevel ( Kireha ) back up to a new primary bevel line ( Shinogi ) in order to re establish the correct angle of descent of the primary bevel to ensure correct geometry. This can change the aesthetic appearance of the Kireha as repairs and polishing can change the colour or texture of the steel depending on the steel composition of the knife.

Original colour of steel will return to the knife through use as the steel regains is patina through natural oxidization. Customers agree to our procedure t&c and aesthetic changes in their knives following servicing.