The depth gauge is a part of the cutting teeth of a saw chain. It determines how deep the cutting tooth gets into the wood while using a chainsaw and the amount of wood planed off. The depth gauge setting should therefore have the proper setting to ensure peak cutting performance. We explain below what to look for.
What is the depth gauge setting?
The gap between the top of the depth gauge and the leading edge of the top plate is known as the depth gauge setting. The larger this setting is, the more wood each tooth planes off.
The depth gauge setting decreases whenever the saw tooth gets sharpened. This is due to the fact that a saw tooth becomes shorter through the filing process and also flatter because of its shape (growing narrower and flatter towards the back).
Therefore users need to inspect and, if necessary, adjust the depth gauge setting every time they sharpen the saw chain to get a good cut.
Adjusting the depth gauge according to the type of wood
Every type of wood has different cutting properties. You can make things easier for your saw by choosing the right setting for the depth gauge.
The resistance when cutting hardwood is greater than it is with softwood. Thus the depth gauge setting should not be too large when cutting hardwood. As a result, the saw chain’s cutting teeth will plane off only a small amount of wood by each cut. If the depth gauge is filed down too far and the gap becomes too big, there is a serious risk of kickback, the cutting performance decreases, the chain tends to “rattle” and the anti-vibration system and even the saw can possibly sustain damage.
The chain pitch provides guidance on choosing the proper depth gauge setting. The following table shows an overview of how large the depth gauge setting should be for hardwood.
For softwood (not during periods of frost), the depth gauge setting can be increased by 0.2 mm. As a result the cutting performance will improve. This is due to the fact that the cutting teeth encounter less resistance from softwoods, such as spruce, alders, etc.
Anyone who frequently switches between different types of trees or cuts both softwood and hardwood should not increase the depth gauge setting.
Filing back the depth gauge
You will find a service mark on the depth gauge so that you can file it back at the proper angle. The contour of the depth gauge must be filed back parallel to this mark. A flat file should be used for filing. Round files are not suitable for this job!
It takes a lot of experience to sharpen a saw chain by hand and maintaining the optimum angle by doing it “freehand” is almost impossible. This is why filing aids are often used. There is a special filing gauge from STIHL for inspecting and filing back the depth gauge. The filling gauge has to be placed in the saw chain. If the depth gauge juts out beyond the filing gauge, it needs to be reworked.
Instructions on how to file the depth gauge are available in our brochure titled Sharpening a STIHL saw chain (PDF).
All mentioned STIHL products are available at your local STIHL dealer.