Набор угловых направляющих для ленточной шлифовальной машины

This is an angle guide that can be screwed to some belt grinder models.

This is used by testing the angle on the guide and then lifting the blade off the guide and moving it to the belt while holding the angle.

Pressing the blade against the guide and moving it to the belt while keeping it on the guide is not intended use.

The guides are:

13° for very sharp kitchen knives

15° for sharp (kitchen) knives

17° for sharp outdoor or EDC knives

20° for general purpose knives and cutting swords

25° for stronger edged blades (some machetes and tomahawks)

30° for hatchets and some other tools

The edge will have the angle of double the guide angel because you need to sharpen the blade from both sides. Razor blades would need a 10° guide.

Don't use a 13° or 15° angle on a 420 blade (or other soft blade steel) as you will get edge rolling really quickly. 20° works fine for cheap 420 stainless knives and gives them a decent amount of edge retention.

I use 20° on most of my knives. 20° is a sharper angle than many knives have when they come from the factory. Steeper angles should be used only on kitchen knives or knives made from very good steel.

Edit: Added 13°, 17° and 30° because they seem somewhat popular for knife and tool sharpening.