What kind of chain to use on a chainsaw. Shape of cutting tines
How to choose a chain for a chainsaw: TOP 13 best chainsaw chain manufacturers
For Russian homeowners chainsaws have long ceased to be exotic. it helps you cut down obstructing trees, collect firewood, get rid of stumps, and all that. without exhausting labor. How important is a chain when you are sawing. no need to explain: its quality and speed depend on its. careless choice of chain can lead to a whole range of disadvantages. wasted money, downtime and having to resort to primitive and time-consuming methods again. That’s why it’s important to know what parameters to look for and which companies to trust.
Published by: Ekaterina Pilnikova Updated: 08.07.2020
Influence of drive sprocket parameters and number of engine revolutions on saw chain speed
When choosing a chain saw, either gasoline or electric, consumers are usually interested in the power of the saw, the length of the bar. The questions about drive sprocket are very seldom asked and even less customers ask about linear chain speed. Let us try to understand the chain speed, i.e.к. it directly affects the performance, ease of cutting, the cleanliness of the wood cutting surface, show the parameters of the drive sprocket that determine it and what the consumer properties of the saw need to pay attention to. There are quite a few physics formulas in this article. If they are bothering you, skip them and move on to the last part of this article. If you are ready to understand it thoroughly, you are welcome to join us in our research.
You will find information on saw engine torque, drive sprocket settings in instruction manuals and on websites. To find the value of the engine speed at maximum power, the chain speed will be even more difficult. Only well-known manufacturers in Europe and Japan give these values, and STIHL is one of them.
Let’s calculate the linear chain speed for ourselves and compare the result with the data in each STIHL chainsaw instruction manual and answer the questions
- Which saw is more productive, cuts faster.
- How chain pitch and drive sprocket affect saw chain speed.
- How the number of teeth of the drive sprocket affects the speed of the saw chain.
To calculate the linear chain speed measured in [m/s] (we will indicate the units in square brackets), we need to know the engine speed, the number of teeth of the drive sprocket and the chain pitch. Let’s assume that the chainsaw has an engine speed of 9000 [rpm], a chain and sprocket pitch of ⅜”, and the number of teeth in the drive sprocket is 6. The chainsaw engine will turn the drive sprocket 9000/60 = 150 [rpm] in one second. Accordingly, a drive sprocket with 6 teeth will turn 1506 = 900 chain links per second. We remember that each driving chain link has a length of 2 ⅜” or 20.375 = 0.75 [“]. About the determination of the chain pitch has been written in this article. Then the distance the chain links will travel in one second is 9000.75 = 675 [“/s]. Consider that 1” = 25.4 [mm] = 0.0254 [m]. So the linear velocity of the chain is 6,750.0254 = 17.145 [m/s]. On pages 49 and 50 of the STIHL MS 180 chain saw instruction manual it is stated that the maximum power is reached at 9000 [rpm] and that the linear chain speed is 18.6 [m/s]. Consequently, the difference between the calculations and the data given by STIHL is 1.455 [m/s] or 7.8%.
Let’s go deeper into the physics of the process and clarify the value of the chain speed.
Let’s find a textbook, a primer, which would describe how to determine the linear speed of a chainsaw chain. We will base our calculations on the theory of chain drives.
Knowing design of meshing of chain and sprocket we see that chain links which are in meshing with teeth of sprocket, are located around it in the form of sides of polygon. The vertices of the polygon correspond to the rivet centers of the chain links in mesh with the sprocket and the number of sides equals the number of teeth in the chain. The chain moves the perimeter of a polygon in which the sides are equal to twice the chain pitch per revolution of the drive sprocket p, and the number of sides is equal to the number of teeth z sprocket. Then the centers of chain hinges when engaging with sprocket teeth are on the dividing circle of the sprocket, diameter d which is determined by the formula:
How to make a proper cut with a chainsaw
This calculation gives us the following result d= 2 ⅜ 25,4 / sin(3,1415 / 6) = 38,1 [mm] (1″ = 25.4 mm). Accordingly the radius r = 19.05 [mm] = 0.01905 [m].
Remember from physics that V = ωr, where
V. Linear chain speed, [m/s];
V = ωr = 9000 2 3.1415 0.01905 / 60 = 17.95 [m/s].
The discrepancy between the calculations and the data given by STIHL is 0.65 [m/s] or 3.5%, which is acceptable in engineering calculations.
Length of chain
It is determined by the number of shanks that are installed in the groove of the saw bar and by which the chain is set in motion. It is not difficult to calculate it on an existing saw chain and you can buy a ready-made chain “in the ring”. Finished chain “in the ring”
The last two digits of the Husqvarna product code indicate the number of shanks. For example, the code 5854042-52 on the package of the Husqvarna X-Cut S93G saw chain. Here “52” is the number of shanks. The chain can also be cut to the user’s length by riveting it from a pre-made coil at an authorized dealer’s point of sale.
Determination of link thickness
Produced by measuring the thickness of the drive link with a caliper. The thickness of the drive (drive) link can have several standard values. The higher the value, the heavier the loads the chain can withstand. Standard values 1.1 mm, 1.3 mm., 1.5 mm. и 1.6 mm. Photo 2 shows an example of measuring the link thickness. Picture 2.
STIHL has a special chain identification system for chain saws that makes it easy to identify a chain by its simple code.
|Chain pitch, inches||STIHL chain pitch designation||Link thickness, mm||STIHL link thickness designation|
- S. Super chisel profile;
- M. Micro half hammer profile;
- D. Duro carbide tipped;
- R. Rescure chain for rescue work.
Sequence of chain links
If you look at any standard saw chain, you always have two tails per cutting link (two driving links). This is the standard and is followed by all chainsaw chain manufacturers. However, there are chains on the market with fewer cutting links, these are so-called half-skip and skip chains. In the first case, an additional connecting link is inserted in every other pair of cutting teeth. In the second case, an extra link is already installed between each cutting tooth. The bottom line is that a standard chain with 64 driving links (tails) should have 32 cutting teeth, which is 50%. But in the case of a half skip we already have 40% of the teeth, and with a skip it is 37.5%. Who needs these chains? Only the cutters are valuable in the chain; they are specially designed and printed and are much more expensive than the connecting links. If it is not possible to make the chain shorter, skipping cutting elements can make the chain cheaper.
Components of a chain saw chain cutter
As a result you can sell it cheaper and make some profit at the same time. But such chain has only negative impact, it makes the saw more aggressive, reduces its performance and even increases the wear and tear of the whole chainrings and the chainsaw itself. It is not recommended to buy such chain, its cheapness does not justify further repair and efficiency. Besides, such chains are not made by any factory, everything is made at home from the factory chains (at best), so it is clear that the quality of assembly and durability of the chain itself is reduced by several times. And buying chain on the market, we carefully study the order of links, in order not to ruin your new machine by this popular method.
- Tire malfunction. Wear on the threaded part of the fastening screws leads to vibrations and a loss of tension. The condition of the clamps must be checked regularly and replaced if necessary.
- Chain stretching. Sooner or later the metal of the links will become structurally deformed and stretched to its limits. As a result, the chain cannot be tensioned. The chain must be completely replaced with a new one.
- Loose or uneven sprocket setting. Have the fault rectified by a specialist workshop. Because accurate adjustment requires disassembly of the unit and removal of many parts.
Check out! There are 3 major causes of chain stretching. inherently low quality metal alloy links, excessive chain tension and poor or improperly selected lubrication.
How to fit
If you have to choose the optimal chain pitch for your chainsaw, it is best to take into account the recommendations of the chain manufacturer and use these recommendations as a basis for choosing the right saw system.
If the manufacturer’s recommendations are not known, it is necessary to choose according to the engine power. The recommended values for a certain pitch are given above.
Important! when choosing, do not forget that the distance between the links is not the only parameter to pay attention to.
It is also worth selecting the thickness of the link, the type of cutting tooth, the number of links. The performance depends more on the cutting angle, cutting depth and the shape of the tooth stop. The sharper the limiting tooth, the faster the cut, and the lower the quality.
Here is a video on chain saw chain pitch selection. In the video it is told and shown how to determine it, for what chainsaws, what pitch to use.
Type of sawing. cross or longitudinal
chainsaws with chains for crosscutting are in demand. Longitudinal sawing is rarely needed, but if you need to use this type of headset, you should consider that such materials are more expensive than conventional ones. The difference between the methods under consideration is that for longitudinal chains the sharpening angle is 5-10 degrees. For cross-cutting models the angle of sharpening corresponds to the value of 25-30 degrees. To clarify this information you can look at the construction of the saw headset.
If the saw cuts awkwardly. causes and what to do
Often sawyers are confronted with the fact that at one moment the saw starts to cut crookedly. This causes not only inconvenience, but also complicates the sawing procedure. The sawyer has to make efforts not only to hold the tool but also to level it. Few people know that operating a tool with such a deformation is prohibited. Let’s find out what causes uneven sawing with a chainsaw, and how it is dangerous for the sawyer.
If the saw starts to cut crookedly, it indicates the presence of a subtle deformation of the bar. Deformation is caused by the tire bead, which has uneven wear. As a result, the chain is not straight, but is slightly skewed. The amount of misalignment may not be visible.
This is interesting! Uneven sawing with a chainsaw can be caused by uneven wear on the chain links or improper sharpening of the chain. Before you replace the bar, first check that the chain is in good condition.
You can eliminate irregular tire wear by changing it. It is almost impossible to mill the beads of a guide evenly, so it is recommended to replace the guide along with the chain. The dangers of a warped chain-saw guide bar are that the chain shank may slip out of the slot, with dire consequences.
A chainsaw bar, like a chain, is subjected to high loads, so it is subject to wear. When wear occurs, it is important to replace the part in good time, before having to wait for the adverse consequences. How to choose, and what to consider when buying a guide bar on a chainsaw, is described in detail in the article.