GETTING STARTED
Unbox your Jotung 7. You'll find that the Tumbler Rolling Knife Sharpener has a Diamond Disc (Top) and a finer grit Honing Disc (bottom) as well that both sides of the Knife Holder are equipped with powerful magnets.
The Jotung 7 is the key to your sharp knife: Each side has two integrated powerful magnets which hold your knife in the exact sharpening angle of 15° or 20°. This way your blade is sharpened efficiently and evenly only over the full cutting edge.
15° sharpening angle
You can use the 15 degree angle for harder blades, for example Damascus knives or blades with a core steel that has a higher hardness degree. These knife edges can be ground to a very fine finish while retaining their stability.
20° sharpening angle
Almost all kitchen knives can be sharpened with the 20 degree angle, as it is a common angle in the kitchen knife industry. You won't go wrong with this one. The knife retains its sharpness for a long time due to the stable cutting edge. The 20° is also suitable for many pocket knives that find their daily use outdoors.
KEEP IN MIND
A 20-degree angle is a more robust angle than the steep 15-degree cutting angle which might offer more precision. Western knives are generally made with a softer variety of steel that is more forgiving to the high-impact style of cutting we do in the West, rendering them too soft to hold a narrower 15-degree angle for very long. Thus, if you change their angle from 20 degrees to 15, they will require more frequent sharpening. Japanese knives usually are made from a harder, more brittle steel that holds a narrower edge for longer and thus can support a 15 degree angle.