STIHL saw chains – features and sharpening
Repetition is the mother of learning. STIHL saw chains, their construction, sharpening, use, areas of application and so on have been discussed before, but for the saw chain, which does the main work when using a chainsaw, repeating these things is never too much.
STIHL produces all its saw chains itself at its factory in Switzerland. All STIHL chains are tested with STIHL equipment and, most importantly, pre-stretched. That means new chains stretch minimally or not at all on first use. Since STIHL itself produces all three important chainsaw components, namely the machine itself, the guide bar and the saw chain, ideal compatibility between these components is ensured.
What do 3/8PMC3 1.1 mm or 325 RMC3 1.5 mm mean?
Saw chains are classified into types according to their dimensions. The most important is, of course, the chain pitch, i.e. the distance between the cutting teeth in inches, giving the types ¼, 3/8, 325 and so on. The next important property is the thickness of the drive link, i.e. the chain gauge, marked in millimetres (1.1 mm, 1.3 mm, 1.5 mm, etc.). This also determines the width of the kerf: the finer the chain, the finer the kerf. At the same time, bear in mind that a finer chain is not as strong as a thicker one, so under heavy loads a finer chain simply snaps. Finally, the type of cutting tooth, which is for example round-edged (also called "chipper"), square-edged, carbide-coated and so on.
Below are explanations of STIHL cutting-tooth types and their areas of application:
PMMC (Picco Micro Mini Comfort)– a home-user chain with a very low vibration level thanks to the cutting teeth "springing" backwards. Low kickback risk, but high cutting performance thanks to its narrow guide groove
PMC (Picco Micro Comfort) – a special STIHL chain developed for use with light, compact saws (home-user and mid-range saws). Low kickback risk, low vibration level, high cutting performance and convenient to use.
PMX – the same properties as PMC3, but with a special sharpening angle for ripping along the grain (sharpening angle 10°) and for use in sawmills.
PS (Picco Super) – the world's first low-profile chain with square-cornered teeth for use on smaller saws. The greater cutting performance from the square tooth makes this chain ideal for arborist work, for example. Excellent cutting performance, low kickback risk, low vibration level and a smooth cut.
RMC (Rapid Micro Comfort) – a comfortable, low-vibration saw chain for semi- and fully professional use on mid-range and professional-class saws.
RSC (Rapid Super Comfort) – a square-tooth saw chain for professional use, high cutting performance, low kickback risk, very good for "plunge" cuts when felling.
PD (Picco Duro) and RD (Rapid Duro) – a saw chain with carbide-coated cutting teeth for especially demanding work and for use where there is a risk of the saw chain coming into contact with soil or other dirt. For example, household work thinning shrubs, sawing on the ground, construction work, trees with dirty bark, and so on. Stays sharp up to 10 times longer than an ordinary saw chain.
|
|
Firewood, household work |
Agri- culture, horticulture |
Forestry |
Tree care |
Carving- work |
Cordless saws |
Electric saws |
Pole pruners |
Chain type |
|
PMMC |
++ |
– |
– |
++ |
o |
– |
++ |
+ |
3/8P |
|
PMC |
++ |
– |
– |
++ |
o |
++ |
++ |
++ |
1/4P 3/8P |
|
PS |
o |
o |
++ |
++ |
– |
– |
o |
– |
3/8P |
|
RMC |
o |
++ |
++ |
– |
– |
– |
– |
– |
1/4 325 3/8 |
|
RSC |
– |
++ |
++ |
– |
– |
– |
++ |
– |
325 3/8 |
|
PD |
++ |
++ |
o |
+ |
– |
– |
++ |
– |
3/8P |
|
RD |
++ |
++ |
o |
++ |
– |
– |
– |
– |
325 3/8 |
++ Ideal
+ Recommended
o – suitable
– unsuitable
Sharpening saw chains
How to sharpen a saw chain?
-
Before sharpening, the saw chain should always be cleaned. Ideally with a resin remover.
-
Check the chain from time to time for damage, and where possible have damaged parts replaced at your local STIHL dealer (damaged tie strap, drive link, cutting tooth)
-
When the saw chain's wear limit is reached, the saw chain must be replaced
NB! To sharpen the saw chain, the chain should be tensioned tighter than usual. This is necessary so that the cutting tooth moves as little as possible during sharpening and so that keeping the correct sharpening angle is easier. After sharpening, restore the normal chain tension.
When is the right time to sharpen a saw chain?
- The saw chain does not feed itself into the material being cut; when sawing you have to push the guide bar into the material
- When sawing, fine sawdust and wood dust fly out of the kerf; with a sharp chain the sawdust should be coarse-grained and dense
- Smoke comes from the kerf when sawing, even though high-quality saw chain oil is used and the chain oiling system is working properly
- The saw chain pulls to one side when sawing; this indicates that the teeth on one side are either blunt or longer/shorter than the cutting teeth on the opposite side
- The saw chain bounces, rattles, jerks and so on when sawing. In addition to the sharpness of the cutting teeth, when these symptoms occur also check the height of the depth gauge
Choosing the right round file
For each saw chain type there is a round file of the correct size. Sharpening a chain with a file of the wrong size gives the cutting tooth the wrong profile, so it cuts either badly or not at all. STIHL saw chain cutting teeth carry a marking that helps determine the chain type if you do not know exactly which chain it is.
| Markings | Chain type | File size |
| 1 or 1/4 | 1/4 | 4.0 mm |
| 2 or 325 | 325 | 4.8 mm |
| 3 or 3/8 | 3/8 | 5.2 mm |
| 4 or 404 | 404 | 5.5 mm |
| 6 or P, PM | 3/8 Picco | 4.0 mm |
| 7 | 1/4 Picco | 3.2 mm |
Using the round file correctly
- When sharpening the saw chain, hold the file firmly with both hands; one hand pushes and the other guides.
- Sharpen only by pushing the file forward, not by pulling it back; on the return stroke lift the file off the tooth surface
- Always start sharpening from the shortest cutting tooth; hold the file so that you can push it from the inside of the cutting tooth towards the outside
- Always hold the file at a 90° angle to the guide bar
- While sharpening, turn the file a little from time to time so that it does not wear out on only one side
- STIHL saw chain cutting teeth have a marked filing-angle line, which is generally 30° (except the PMX ripping chain)
- Hold the file so that a quarter of the file's diameter is above the cutting tooth
Checking the sharpening quality
If darker areas are visible on the cutting edge of the tooth, the cutting tooth is not yet sharp. The cutting edge is correctly sharpened when the entire cutting part of the tooth is uniformly bright.
After sharpening the cutting teeth on one side of the saw chain, turn the saw 180° and sharpen the cutting teeth on the other side of the chain in the same way. All cutting teeth must be the same length as the shortest cutting tooth on the saw chain.
Filing the depth gauge (the so-called "raker")
- Place the depth-gauge filing gauge on the chain; if the depth gauge protrudes above the corresponding slot of the tool, file it lower with a flat file.
- File the depth gauge until it is level with the corresponding slot of the depth-gauge filing gauge
- On saw chains where the depth gauge is in two parts, both must be filed at the same time
- File the depth gauge at the same angle as shown on the tooth. Do not file the tooth lower than the highest corner of the lower part of the depth gauge. NB! When adjusting the depth gauge height with a flat file, take care not to accidentally damage the freshly sharpened cutting tooth.
STIHL's tips
- By following these rules you will achieve perfect sharpening results, and the side and cutting-edge angles of the cutting tooth will also get the correct values
- Mark the shortest cutting tooth with a marker.
- Sharpen in batches of two or three file strokes and check how much material has been removed from the cutting tooth and what the cutting surface of the tooth looks like. If the cutting surface shines uniformly, do not sharpen that tooth any further (unless the length of the cutting tooth needs to be shortened).
- The depth gauge may be filed up to 0.2 mm below the filing gauge if cutting soft wood under normal conditions (not in cold weather). A lower depth-gauge level can also be set using the filing gauge for the next chain pitch (for example, using a 325 chain gauge on a 3/8P chain, etc.).
- When sawing, do not wait until the saw chain is completely blunt. Run the file over the cutting teeth a couple or three times periodically (for example at every second refuelling) so that the chain easily gets maximally sharp again.
- If the length of the cutting teeth does not need to be corrected (all cutting teeth are the same length and/or worn equally), count the file strokes needed to sharpen one cutting tooth and sharpen all the other teeth with the same number of strokes.
- If the cutting teeth on one side of the saw chain are longer (the chain starts to "pull" to one side when sawing), more pressure was used when sharpening the teeth on one side. Correct the length of the cutting teeth by running the file one or two more times on the chain side with the longer cutting teeth.
STIHL sharpening aids for easier saw chain sharpening
Maintaining and preserving the correct filing angles, depths, pressures and so on purely by hand sharpening is actually extremely difficult and requires a lot of practice. That is why STIHL has several aids for easier and faster sharpening
Depth-gauge filing gauge
1. Slot for checking and setting the depth gauge height
2. Check openings for checking the cutting tooth filing angle
3. For cleaning the guide bar groove and checking the groove depth. Can also be used for measuring the lengths of cutting teeth.
4. Check openings for checking the side angles of the cutting teeth
Depth-gauge filing gauges are available for all chain types; check that you use the correct gauge when sharpening your chain.
File holder
The file holder helps keep the round file at the right height and the right angle while sharpening. File holders are also different for each chain type.
FF 1 file holder guide
If you do not want to keep the angle by eye alone when sharpening, it helps you more easily maintain the 30° filing angle. The guide also holds the file holder at a 90° angle to the guide bar. Guides are also different on different file holders
2-in-1 file holder
With this file holder it is possible to sharpen and adjust the cutting teeth and the depth gauges in a single operation. Like an ordinary file holder, the 2-in-1 file holder also keeps the round file at the right height when sharpening the cutting tooth. The shape of the handles and the markings make it extremely easy to follow and achieve the 30° filing angle.
FG4 roller file guide
The FG4 file guide is an ideal helper for hand filing without a holder. There is a separate guide for each chain type, just like the round file. The guide sits directly on top of the chain on the guide bar and helps guide the round file as needed. The filing angle is ideal when the file moves freely on the two large rollers inside the guide without any obstruction. The guide also helps to hold the file at 90°. In addition, the FG4 guide has a separate folding gauge for checking and setting the depth gauge height!
SOURCE: https://www.farron.ee/blog/mootorsaekasutamine/
A useful instructional video:
