At first glance, sharpening chains of chainsaws with your own hands is a rather difficult and long task, but with special sharpening devices, this process will not be more difficult than sharpening other cutting tools. In this article, we will talk about how to sharpen a chain of a chainsaw.
Principle of operation and blunting of chain links
Chain link tooth has rather complicated geometry. The upper and side cutting edges are inclined relative to each other at a certain angle, which makes the sharpening operation difficult. Slicing wood with a tooth in a chain is like working with a planer, and the thickness of the cut layer is controlled by the thickness of the limiter.
During intensive work, the saw teeth become dull quickly. During the day, sharpening may be necessary several times. This problem is especially aggravated by the meeting of the chain with the ground. It is enough to hook the ground with a tire once for a couple of seconds, and you need to stop working due to the fact that the saw itself ceases to go deeper into the wood, and the chips become quite shallow.
The more often you sharpen your dull teeth, the less material you have to remove when sharpening a chain of a chainsaw, and it will last longer. Determining that the time has come for sharpening is fairly straightforward. The easiest way to do this is to listen to your feelings when cutting: a properly sharpened and sharp chain is drawn into the notch with a little pressure, and if you have to make an effort, the teeth become dull. You can also understand that it’s time to sharpen the chain. by chip size, inflying out of the cut. A long thick chip can only be with a sharp chain, and a small one indicates that it is time to sharpen the chain urgently.
Running a chainsaw with a blunt or defective chain is highly discouraged. The result of her work may be fatigue in the hands and torso and poor cutting results. It also entails a significant decrease in productivity, increased wear of all parts of the chainsaw and greater fuel consumption.
Angles and link parameters
The correct sharpening of the chainsaw chain is impossible without knowledge of the parts of the link and the angles at which they should be sharpened.
The main parts of the cutting link:
- Tooth blade
- Depth gauge
- End blade
- Upper blade
Top blade angle, the rake angle and the angle of sharpening can change when sharpening. These angles greatly affect the cutting properties of the chain. It is advisable to comply with the recommended values of these angles.
Each cutting link in front of the tooth blade has a depth limiter. The difference in height between the front edge of the tooth back and the highest point of the depth gauge is called the distance of the depth gauge. Depends on this distance the depth to which the upper blade will cut into the wood and, consequently, productivity. This distance is set depending on the type of execution and the chain pitch. Its average value is 0.6 mm and can vary in both directions by 0.2 mm. The consequence of higher values of this parameter will be a greater tendency to recoil, too much capture and vibration of the chainsaw. And its low values will lead to a loss in performance.
With each subsequent sharpening of the chainsaw due to the reduction of the upper face of the tooth, the height of the cut chips decreases, therefore, every 5-10 sharpenings, the depth gauge needs to be filed.
The main angles of the chain links:
- The depth at which the upper blade cuts into the wood is regulated by its rear angle. It is formed from a tooth back that slopes at an angle back.
- The rear corner of the end blade is formed from a tapering tooth blade. Its purpose is lateral chip cutting.
- The rake angle is formed from the edge of the end blade relative to the sliding surface of the cutting link. For different chains, this angle can vary from 60 to 85 degrees.
- The rear angle determines the amount of tilt of the upper blade back and is measured from the sliding surface of the cutting link. And for different circuits it can have values from 50 to 60 degrees. The main blade of any link in the chain is the upper, and the rear corner of the upper blade is the most important angle. This angle is quite difficult to measure, but subject to other prescribed values, it is formed correctly.
- The angle of sharpening or the angle in the plan is the angle from the perpendicular to the guide rail to the upper cutting edge. It can be changed depending on the type of wood that you are going to saw. A larger sharpening angle increases the cutting performance of soft unfrozen wood, and its smaller value allows you to cut hard and frozen wood more smoothly and with less vibration. However, sharpening angles of less than 25 and more than 35 degrees are not recommended. As an exception, chains for longitudinal cutting are produced, this angle of which is 10 degrees.
Video: How to Measure a Chain For a Chainsaw
Chainsaw chain sharpening rules
Since the internal contour of the tooth in its shape is quite close to circle, and the chain is made of fairly soft metal, sharpening is done with a round file having a small diameter. For proper sharpening of the chainsaw, you need to accurately position the file relative to the tooth. The upper edge of the file relative to the upper edge of the tooth should protrude approximately 1/5 of its diameter. Before sharpening, find out the parameters of your chain, since the diameter of the file is selected depending on the pitch of the chain. Usually it is 4-5.5 mm.
The most common set for sharpening the chain includes a round file on a special holder, a flat file to reduce the depth gauge, a template for the last operation and a hook for cleaning the chainsaw from sawdust.
The lines that are on the holder with a round file allow you to correctly position the tool relative to the chain. In line with orientation lines the holder is placed on the sharpened tooth. It lies on the top edge and depth gauge, and the file is located under the cutting edge.
The holder allows you to fit the file to the tooth at the correct height. For chains with different pitch, there are different holders. Choosing the right holder and the right diameter of the file will allow the latter to protrude 1/5 of its diameter above the tooth back. We strongly recommend sharpening chains of chainsaws to use only special files.
Before starting sharpening, it is advisable to fix the tire. When working, it is necessary to make 2-3 movements of turning from yourself, while firmly pressing the file to the edge of the tooth and without changing the position of the holder. Do not press the file too hard move it smoothly and measuredly. The file must be rotated regularly to avoid clogging and unilateral wear. With this operation, all other teeth are also sharpened. For greater convenience, first sharpen all the teeth of one direction, and then the teeth of another direction.
When grinding teeth, try to ensure that the pressure and number of movements are the same for each tooth. Due to this, the teeth will have the same length. In the opposite case, the chain will have an uneven course and crack formation is possible in it. The difference in tooth size can be eliminated by sawing all the teeth to the length of the shortest.
After 5-10 sharpening the teeth you need to grind depth gauge. A template is used for this. It is laid so that the limiter protrudes from the slot, and this protruding tip is ground with a flat file.
The design of another set has differences, but the principle of its operation differs little from the one described above. It uses the same round and flat files, and a universal special template allows you to properly sharpen the cutting tooth and depth gauge. In the case of sharpening the cutting tooth, the chain must fall into its slots. The file is superimposed on the template and brought under the cutting edge, resting on the guide rollers. The file should move along the side edges of the template.
Before grinding the height limiter, think about which wood you will be sawing in the near future. For softwood, the stopper is inserted into the slot labeled “Soft”, and for hardwood, it is inserted into the slot labeled “Hard”. Stitching the height limiter, as with the first fixture, should be done with a few smooth movements of the flat file.
Chain sharpening machines
If the chain smelled rather strongly of gravel or sandy soil, then it is unlikely to be able to sharpen it qualitatively with a file. Also file sharpening will not help with heavy chain wear, because she lost her form. In such cases, it makes sense to use special machines. Such machines are divided into electric and manual.
An electric machine is the best tool for sharpening chains. It is universal and has many settings and advantages, such as:
- setting the chain at the right angle;
- eyeliner precisely to the sharpened edge;
- automatic vise clamping when the disc is lowered onto the chain.
However, its only drawback is the high price. Its purchase is only suitable for workshops and enterprises involved in the extraction of wood.
Hand tools also give a good sharpening result, and the price of some of them can be commensurate with the devices described above. We will describe the principle of their operation using the example of two models of manual machines manufactured by Stihl.
The design of these devices resembles a beam saw, which has a file instead of the blade. A model called "FG 1" is installed directly on the tire chainsaw, and "FG 2" is stationary. These machines are good in that you can not only sharpen the chain, but also fit them to the size of the smallest tooth. Although the tuning mechanism is quite heavy, it allows you to sharpen the chain with any tooth parameters and save this setting for subsequent teeth and chains. This makes the teeth perfectly identical to each other.