This is also not mentioned in the instructions. It's a learning experience. The more you file the duller the chain gets if you do not pay attention to the rakers.
using one of these type file guides and having the wrong size file in the guide and also using one of these type guides and NOT setting the raker depth BEFORE using the guide. (if rakers are too high the file and guide is too high on the tooth when the tooth is worn about 1/2 way back) File is actually dulling the tooth as you file, because the raker is holding the guide and file too HIGH on the tooth. The guide works great to just do a fast touch up of a chain that has 75% or more full size tooth.
The correct size file is usually not marked on the metal guide, just on the paper package.
Oregon 25894 5/32" 4mm Chain Saw Blade File Guide
using one of these type file guides and having the wrong size file in the guide and also using one of these type guides and NOT setting the raker depth BEFORE using the guide. (if rakers are too high the file and guide is too high on the tooth when the tooth is worn about 1/2 way back) File is actually dulling the tooth as you file, because the raker is holding the guide and file too HIGH on the tooth. The guide works great to just do a fast touch up of a chain that has 75% or more full size tooth.
The correct size file is usually not marked on the metal guide, just on the paper package.
Oregon 25894 5/32" 4mm Chain Saw Blade File Guide