The choice of gasoline saws is determined by several criteria. One of them is the pitch chain chainsaw. This parameter determines the capacity of the equipment for cutting materials and must match the engine power, only in this case it will be possible to extend the life of the tool and reduce the specific consumption of fuel.
Selection step chainsaw chainsaw.
The concept of the step and its meaning
Under the pitch chain imply the distance between any three rivets. In chains for saws, this length characterizes the distance of two cutting teeth relative to each other. The step size is equal to the length between the vertices of two adjacent shanks of the chain (guide elements that go into the groove of the tire). In order to correctly determine the chain pitch of the chainsaw, measure the distance between the axes of three rivets running in succession.
Chainsaw gasoline design.
There is a reasonable pattern that says that the greater the distance between the cutting teeth of the chain, the deeper they go into the material being cut. By increasing the chain pitch of the chainsaw, you can increase its performance. In this case, accordingly, the force for rotation of the drive sprocket changes. It is necessary to understand that the higher the step, the more force must be applied to pull it during the cutting of the material and the greater must be the engine power.
Modern manufacturers of gasoline saws use three main types of sawing chains with the following pitch values, measured in inches:
- 0.375 (used in the classification label 3/8);
The quality and accuracy of the cut created in the material depends on the chain pitch. If the quality of cutting when working with a chainsaw is not of global importance, then the accuracy of the cut is sometimes important when dissolving logs or planks, for this it is necessary to take into account the dependence of the saw step on the dissolution of wood according to specified markings.
The position of the file when sharpening the chainsaw chain.
The higher the distance between the teeth, the more vibrations and parasitic forces arise, which tend to displace its working tire in different directions, and the coarser is the cut created due to the breaks in the wood fibers. Accordingly, the effort is increased to hold the saw in the hands.
The selection rule of the chain indicates that the step between the teeth is directly proportional to the performance, the reserve power of the motor and inversely proportional to the accuracy of the cut created.Back to table of contents
Matching engine power and distance between the cutting teeth of the chainsaw chain
Based on the data obtained experimentally, it is recommended to make a choice of chainsaw, considering the ratio of drive power and the distance between the cutting edges. It is known that the higher the pitch, the more force must be applied to rotate the drive sprocket and the greater must be the maximum torque developed by the gasoline engine.
To choose the right tool configuration, it is necessary to use the data of the minimum power values for each of the three typical steps of the chains.
Critical power ratings of gasoline engines driving the drive:
The value of the chain pitch.
- step 0.325 ”- power not less than 1.8 hp (1.47 kW);
- Step 3/8 ”- power not less than 3 hp (2.21 kW);
- step 0.404 ”- power not less than 4.5 hp (3.31 kW).
If the power of the driving engine is less than the specified values, then the following phenomena are possible during the dissolution process: a chain seizes in a tree, a decrease in the speed of rotation of the drive leading to overheating of the motor, an increase in sawing time and increased operating costs for fuel.
The use of powerful motors with a chain, having a small step, is impractical, since it will also increase the time for dissolution and increase in fuel costs. However, this combination is allowed when you need to perform precise work with wood.
The indicated minimum values of the characteristics of the drives show the ability of the equipment to work reliably, but do not show the time of its continuous use in a professional environment. Rather, these values are given as recommendations for performing occasional work or for operating conditions of the instrument with long interruptions. For long-term use of equipment that implies a professional mode, the following technical data conformity is required:
- pitch 0.325 ”- power 2.5 hp (1.84 kW);
- Step 3/8 ”- power 4 hp (2.94 kW);
- step 0.404 ”- power 6 hp (4.41 kW).
The choice of tool should not be justified by the desire to have the greatest possible pitch of the chain, as this entails the presence of a powerful motor, a long tire, which makes the saw much heavier.
And if, for example, it will be used sporadically or for carrying out country work, then such a choice is not appropriate.Back to table of contents
Dependence of a step on additional characteristics of saw chains
Comparative table of characteristics of chain saws.
During the movement of the chain and the cutting of wood, very high loads act on it, in connection with this an important characteristic is the thickness of the element of the link entering the tire groove and sliding in it. This value also indicates the thickness of the fastening elements of the links. You can measure it with a standard caliper.
Typical values of the thickness of the guide element:
- 1.1 mm;
- 1.3 mm;
- 1.5 mm;
- 1.6 mm;
- 2.0 mm.
Thicknesses of 1.1 and 1.3 mm are used for the manufacture of entry-level chains intended for minor work. Most often, the step length with these values is 0.325 ”, which implies a gentle mode and low loads.
The size of 1.5 mm is the most common on the market of chainsaws and accessories, this value is sufficient to ensure safe operation at step 3/8 ”. However, this value will always say that the chain is not intended for professional activities.
Guides that are 1.6 and 2.0 ”thick are designed to handle the most complex work, that is, they allow for the use of equipment in shifts. At the same time, you need to know that these two values are a specific classifier, indicating that the metal for the manufacture of these chains is smelted from special steel grades, that is, increased strength is embedded in the structure.
All manufactured chains may vary in depth. It is characterized by the height of the cutting tooth (profile). The height is measured between the upper edge of the cutting edge and the limiter (all this is on the same segment). There are low-profile and high-profile chain products.
Chain pitch (a / 2) and shank thickness (b).
The higher the profile, the higher the entrance to the wood and, accordingly, the speed of sawing. The height of the profile affects the occurrence of vibrations, which can cause increased wear of the drive or the difficulty of holding the tool in the hands, the higher the cutting part, the stronger the vibrations. Also, a high profile circuit requires increased engine power.
Household chainsaws always have a low profile chain. Professional devices combine different options, but always adhere to the fact that if the circuit is at a large pitch, then its profile is low, and if the step is 0.325, the profile is made high.
Such variations make it possible to increase the cutting speed not in increments, but in profile height (depth of cut). However, most professional tools for felling focus on increasing the pitch, not the height of the profile, arguing that the chainsaw is more controllable in this version.Back to table of contents
Some important points when choosing chains or chainsaws
There are other indicators that affect the performance of the tool and the specifics of the work.
Values recommended to take into account:
- cutting tooth geometry (profile);
- the number of cutting links;
- type sharpening cutting edge link.
The structure of the chain saw.
The cutting profile is of two types: chisel and chipper. The first option has a straight work surface and is more productive. The second type has a sickle shape and reduced performance. In service, the chipper chain is easier, since it is easier to sharpen, it does not require strict adherence to sharpening angles. Chisel variants are more often applicable in 3/8 and 0.404 steps.
The number of cutting teeth is always determined by their ratio to the number of guides included in the tire saw. That is, the link with the cutting part has two guide links. If such a combination is not observed, it means that the chain is of dubious production.
The type of sharpening cutting profiles is governed by the type of future work. Typically, a classic chainsaw is used for cross-cutting wood and extremely rare for longitudinal. In rare cases, there are chains with cutting links that are oriented for longitudinal cuts.Back to table of contents
Selection Guidelines and Chain Interchangeability
When purchasing a tool, you need to clearly understand the scope of its use and, depending on this, determine the desired chain pitch.
Chain links: a - cutting or cutter, b - locking.
Conventional types of use of chainsaws for private users:
- pruning branches in the garden, simple summer work;
- individual construction, preparation of firewood, occasional felling of trees;
- frequent use (implying the execution of works for hire), the procurement of very large amounts of firewood, operation in its own workshop.
In the first version, a chainsaw is recommended, having a chain with a small (0.325 ”) pitch. This will allow to get an easy and maneuverable tool, it is easy to produce pruning of branches, including climbing along ladders and branches of trees. This equipment allows for the simple dissolution of wood, and occasionally it is allowed to conduct felling of small trees.
The second option involves the choice of a saw with a step of 3/8 ”and the thickness of the guide link at least 1.5 mm. Such saws make it easy to carry out the full range of maintenance of the site, a small workshop, to procure a stock of firewood for the winter.
The third option offers the use of 3/8 and 0.404 ”chains paired with a powerful engine, since the list of work performed is intended only for a professional tool, it is important to take into account the thickness of the guide, it should be 1.6 or 2.0 mm. Steel for the manufacture of such chains is made with regard to possible overheating during the dissolution of wood without losing the hardness of the cutting edges of the links.
The main parameters of the chainsaw chain.
Interchangeability of chains is allowed only at the step size provided by the manufacturer. This is explained by the number of teeth of the drive sprocket, which is calculated only for a certain distance between the links. The chainsaw tire has a groove for a certain thickness of the guides, this should be considered when changing the chain.
It is not recommended to replace the drive sprocket under the larger pitch due to the occurrence of a mismatch between the power and the load when dissolving wood. A weak motor will not develop the necessary power for pulling the cutting links along the tree, which will lead to jamming or failure of the drive and the coupling of the device.
The most universal chain has a pitch of 3/8 ”, this allows for multilateral use, combined with a high cutting speed and a fairly accurate cut line, satisfactory de-racking of wood fibers.Back to table of contents
Precautions when choosing chains for chainsaws
Chain change should occur with strict adherence to technical parameters. If there is no classification, then the following data must be known:
- the number of leading links;
- the thickness of the guide included in the groove of the tire;
- brand saw.
The new chain should be loosely fitted with an asterisk, and the guides should fit into the groove of the tire. After adjusting the tension should be free scrolling without wedging. This will speak about the correct selection.
Known global chain manufacturers for chainsaws, producing decent products from the desired steel. It is advisable to buy such products, as Chinese-made products are of dubious quality, and at best there will be a rapid loss of the ability to cut wood, and at worst, under heavy loads, the chain may break.
When buying a new product, according to individual criteria, one should be wary of various promotional items with a low price. There are certain cost limits for such devices. So, professional-grade chainsaws with 3/8 ”increments and higher cannot cost less than $ 1,000. This is due to the use of components of the highest quality both in the equipment itself and in the chain.
The modern market has a huge selection of chainsaws, which are positioned as professional, worth about $ 100-200. It is clear that this tool will soon become worthless. The term "semi-professional" has recently been adopted. In fact, there is no chainsaw with such a level. There are household saws for professional work related to wood. This should be known and taken into account.
Saws of serious level for many-sided application are made. They involve the use of chains with different pitch, which allows for any work. Naturally, replacing the chains in these devices means replacing the sprocket, the only difference is in the ease of installation and the ability of the engine to pull the links in long strides.
Based on the above, it is required to add that when making a purchase, you need to pay attention to the chain pitch and after that to the compliance of the engine. This indicator is the decisive criterion in the ability to cut wood with the lowest cost of resources and at high speed.