The first step in the repair and overhaul process
All known methods of saw chain shortening presuppose criteria of damaged cutting and connecting links rejection, the sequence of working operations defined by technology. The cutting and joining links are mounted with factory rivets, which in all respects comply with the standards in force.
Use of self-made components is not recommended in any case. Special rivets for chains are rare to find on sale, so in most cases the problem is solved by installing the right parts removed from the dismantled section of the chain.
How to tension the chain on a Partner 350 chain saw
Buying a chainsaw be ready to have to master not only the skill of sawing logs and chopping trees, but also the repairing of the tool. It is imperative that you read the instruction manual and check that the saw works correctly, in other words, test the tool. If it is smooth and even, but the saw may wobble or refuse to cut through a log at all, it is a good idea. The first thing chain tension on a chainsaw that seasoned professionals always look for is.
Reasons for chain slackening on a chainsaw
The chainsaw is made up of the guide bar and the chain itself. Each part can fail, affecting the function of the mechanism.
There are several good reasons for chain tightening on a chainsaw. Even with a tensioned pulley, even after sawing a few logs, you may experience slack in the element. The main causes of malfunction are:
Link stretching occurs continuously due to the nature of the design. In order to perform its task, to follow a given path and to cut wood, it consists of many sharply sharpened links at a certain angle. The bushings are used to connect them to each other. There is a backlash between them, gaps.
Correct Way To Adjust The Chain Tension On Your Chainsaw
When the temperature of the metal rises during operation, this backlash increases, the steel expands and lengthens, and the working blade deforms.
Potential problems in one part of the design cause others to be disturbed, as they are combined into a system. It is therefore important to pay attention to the malfunction of the saw at the outset, to replace the broken part or to adjust it in good time.
Possible reasons of the tensioning of the main part of the chainsaw may be the work in unfavorable conditions (ingress of dirt, dust), improper work of the oil pump (no lubrication of the links), the use of low-quality material.
The bar is loose
Guide rail. chain on electric saw. The chainsaw is made from stainless steel whose operating characteristics have an impact on durability. When a part wears out, it must be replaced and cannot be repaired. If the bar is loose, it is often due to overheating of the blade, which can occur for several reasons besides the age of operation:
In addition to changes in the parameters of the guide bar, the work area itself can also be stretched. As the main part of the tool, it is directly responsible for the quality of the cut.
The chain is stretched
The risk of the working area sagging is higher with a new construction or after extended use. The causes of stretching can be:
The longevity of the metal belt depends on the operator’s operating style. If a household tool is used with a heavy load, the service life is shortened.
Problems with the chain drive sprocket
The chainsaw is designed so that the engine has to transfer power to the bar where the teeth are located. A sprocket-shaped part is for this purpose. It receives, stores and transmits power from the engine continuously, and heats up during operation. The life of the drive sprocket is affected by the pitch of the teeth, the angle at which they are positioned, and how properly sharpened.
If you do not make the chain tension on the chainsaw in time and do not replace the part, it is fraught with expensive repairs:
- The blade begins to cut on a curved path;
- the load on the engine increases, increasing the risk of engine failure;
- the clutch spring breaks;
- the motor piston of the tool is deformed.
The instruction to your saw specifies the standards under which a part of the mechanism is operated. If it deflects more than 0,5 mm you need to change the sprocket.
Does the chain always need to be repaired?
Chain slack in a chainsaw is not always a reason to repair it. It is necessary first to make sure that it is finally not subject to tensioning (adjustment).
Stretching of the chain due to prolonged use is a typical case. The chain metal heats up during operation, and the links gradually stretch due to expansion of the metal volume. That is, the chain is pulled out every time, which can sometimes be eliminated by partially reducing the cutting time. But this is not the solution when you have to use it intensively all shift long in industrial environments or when preparing firewood for the winter.
Another circumstance that prevents normal operation of the saw, even with a new chain, is a mismatch in length. This can only happen when purchased by inattentive users, or caused by the current lack of the right chain. Which is not dangerous at all, because it is always possible to find a solution by shortening the chain manually. In this case, the strength of the connection of the chain links will remain at a fairly high level.
Chain tensioning is usually done manually by means of the saw’s tensioning bolt in the area of the toothed stops.
Using a straight screwdriver placed on the bar and the drive sprocket, the chain, after closing the side cover, begins to gradually tighten.
Do not pull the chain as far as it will go, because you risk pulling the chain links out again soon. Usually there is a small amount of chain tension that can be checked by hand. It should give way slightly from the guide bar by about a millimeter.
Why the chain comes off the chainsaw or electric saw?
Owners of chainsaws occasionally encounter a common problem: the chain starts to come off their chainsaw or electric saw. Why this is the case, we will explain later in this brochure.
The Hidden Chainsaw Killer : Chain Stretch. How Do You Deal With It?
There are only three main causes of chain fly-off:
Let’s look at why this or that problem occurs:
If the chain is stretched, starts to sag, slips off the bar
The cause is most likely in the wear of the component itself. The chain has a finite life and is the wearing part of a chainsaw or electric saw that wears out most quickly. The metal is deformed due to the loads, so it not only becomes blunt, but also becomes about 1 cm. longer than on a new machine. The simplest way is to change a component, that is to buy and establish a new chain.
On how to perform tightening and whether in general it is possible to tighten the chain at home, in the review.
If there is a problem with the bar, it is in the place where it is fastened.
This cause is quite common: in the groove located between the outer plate installed on the chainsaw headset and the inner plate located on the body of the chainsaw or electric saw. The cover is usually bolted in place. This attachment is called the motor unit. The mounting of the sprocket, like the drive sprocket, is covered with protective covers. When the fastening bolts loosen, the degree of vibration of the tire increases and it begins to move.
If there is nothing wrong with the bar, the tensioning is correct, and so is the function of the tool itself. If it is loose chain and chain looseness that is causing the chain to slacken, fasten the guide bar and check the chainwheel.
If the drive sprocket is not properly secured, the chainsaw chain will also need tightening, because sagging is unavoidable. Fix the sprocket bar by removing the engine guard, spark plugs, and pulling out the air filter. The spark plug is replaced with a stopper whose main purpose is to hold the piston in place. Next, use a special wrench or a universal wrench for angle grinder to turn the clutch disk in clockwise direction.
Make sure that the piston is in its end position. if you look into the spark plug hole, the piston should be at the bottom.
After fixing the piston, you can start clamping the drive sprocket. Next, reassemble all items in reverse order.
Rebuilding your chainsaw tire to install a shorter chain
Figured it out. Turns out I had a shortened chain saw chain on hand. Using the Allen wrench that came with the saw, remove the cover to attach the new chain to the old bar, and realize that just trimming the tail isn’t going to be enough. You can clearly see in the photos that the length of the longitudinal groove on the bar with the shortened chain is also missing, which means it will have to be lengthened. I assembled the saw, made sure everything that moves moves without friction and interference, refilled the chain oil and fuel mixture and put my Husqvarna into operation.
Gearbox transmits torque from motor to cutting tool. Automatic brake interrupts chain operation if chain breaks, bounces off the tree being worked, or if abnormal operating modes occur.
Breakdowns of saw chains and guide bars: Causes and symptoms
This article gives examples of common breakdowns and malfunctions of the saw unit (bars and chains), with photos of damaged parts and an analysis of the causes of the breakdown.
Now you can learn by what signs the experts determine whether your case is a warranty, and why their reviews of the causes of failure are often so categorical. It’s simple. the vast majority of chain-saw violations (poorly tensioned chain, running dry or blunt chain) cause breakdowns with distinctive external signs.
Material prepared by STIHL for service technicians and kindly provided by the editors.
A very frequently asked question: Why does a chain fitted to a saw move, but not cut?? This is usually affected by four factors:
- Saw breaks (e.g. carburetor is dirty and chainsaw won’t reach full speed);
- The chain is blunt (just need to sharpen it);
- The chain is not installed correctly (cutting edge backwards);
- The drive sprocket is completely worn (completely cut through the crown or sprocket).
Damage analysis of the saw headset
1.1 Saw chains / drive links
Damage picture All front and rear drive links are riveted. The reason a. Loose chain tension. б. Wrong pitch between chain and sprocket;. Wrong pitch between sprocket and chain. в. The chain is new but the sprocket is old. Remedy a. Replace saw chain. Correct tensioning. б. Change saw chain. в. Install a new chain sprocket with the correct pitch.
Damage pattern Broken or broken out nose on several successive drive links. Cause a. The chain breaks. These links have piled up on the chain sprocket. б. The chain has been tensioned too loosely and has slipped off the sprocket. Corrective action Replace the saw chain or the damaged part of the chain chain with the surviving part. Correct tensioning.
Damage pattern The backs of all drive links are rounded. Cause Chain is too long. Pitch mismatch between chain and sprocket pitch. Lack of lubricating oil. Corrective action Change chain sprocket and chain. Always use the correct chain lubricant.
Damage pattern Concave rounding on the spouts of all the drive links. Cause Groove depth on the Duromatic guide bar head is too shallow. Fixing Replacing the guide bar.
Damage pattern Dull blows on all drive link sprockets. Cause Guide bar groove depth too shallow. Remedy Change guide bar.
Damage pattern The tips of the nose on all driving links are pinched. Cause Sprocket teeth are worn on the sprocket tooth base, chain sprocket tooth tips due to runout if the chain is too loose. Remedy Change chain sprocket and chain. Re-tension the chain correctly.
Damage pattern Nicks on both sides of the nose of several drive links. Cause Poor tensioning of the chain. Drive links are slipping out of the bar groove and are hanging up on the bar nose or where the bar runs over. Remedy Correctly tension the chain. Check the bar groove at the point of overlap; widen the groove if necessary.
Damage pattern Worn out side faces of nose of all drive links, tips rounded. Cause The saw chain is loose in the guide bar groove as a result of wear or expansion of the guide bar groove. Remedy Slotted guide bar crimped or replaced.
Fault pattern Worn-out sprockets on all drive links look like an hourglass. Cause The saw chain vibrates in the bar groove due to uneven sharpening of the cutting teeth in both rows of teeth. Repair Correctly sharpen chain. If the bar groove has worn too much, replace the guide bar.
Damage pattern Unilateral side wear of all tooth tips. Cause Cutting teeth of one complete tooth row are not properly sharpened. Remedy Sharpen chain properly. If the guide bar groove is too worn, replace the guide bar.
1.2 Saw chains / cutters and connecting links
Damage pattern Uniform wear on all cutting links up to the wear marking and on the connecting links. Cause Normal cutting with correctly sharpened and tensioned chain if the chain is well lubricated. Corrective action Change chain.
Damage pattern Excessive wear under the lower connecting rivet of all cutting teeth and opposite connecting links. Cause a Tooth flank hangs backwards. b Tooth end hangs forward. c Depth stop distance very large. d Blunt blades. e Chain tension is loose. Correctly sharpen all teeth. c Grind all teeth to the prescribed depth stop distance. Correctly tension the chain.
Damage pattern Slant wear on sliding surfaces of all cutting teeth and opposite connecting links. Cause Chain tension is loose. Too much pressure to cut blunt and/or blades with a large rake angle. Correctly sharpen and tension the chain.
Damage pattern Excessive wear on the sliding surfaces of all cutting links and connecting links with only minor wear on the tooth blades. Cause a The chain runs dry. b Too much pressure to cut with a blunt chain with a short stop distance. Remedy a Checking the chain lubrication. b Correctly sharpen chain. Finish depth stop.
Damage pattern Concave sliding surfaces on all links. Cause Chain tension is too low. The chain is running dry. Working in this operating environment causes excessive heating of the saw chain and cracks in the connecting links. Correctly tighten the chain Correctly tighten the chain. Check chain lubrication. Note Affects mainly Duromatic guide bars.
Damage pattern Crack under the rear rivet of one or all of the cutting teeth of the opposite connecting links. Reason a Cutting teeth are blunt. b Tooth end hangs backwards. c Tooth end hangs forward. D Length of the depth stop. e Too much pressure to cut with a damaged chain a) and b). Solution Replace the chain.
Chainsaw Chain Stretch. It’s real and this is how you can minimize it.
Only one or all of the cutting teeth and opposite connecting links are cracked under the front rivet. Cause Depth limiter spacing is too short and thus too much pressure is applied to cut with the chain. Remedy Change the chain.
Fault pattern Crack under both rivets of one or all links. Reason a Dull cutting teeth. b Tooth end hangs backwards. c Tooth end hangs forward. d Incorrect depth stop distance. e Too much tension in the chain: especially at low temperatures. Corrective action Change chain.
Damage pattern Chipped or broken leading edges on all chain links. Cause a Small chain sprocket diameter. b The bar groove at the entry point is too wide. The chain breaks when entering the bar groove. Solution a Adjust the sprocket to match the guide bar. b Properly tension the chain. Repair the tire. Note If the chain hinges have become stiff, replace the chain.
Damage pattern Flattened notch on all cutting links, heavy burrs on sliding surfaces and bar. Cause a Tension of the chain is too low or not evenly sharpened. b New chain is running with a worn sprocket or at an incorrect pitch. Solution a Resharpen and tension the chain correctly. b Replace chain, sprocket and bar.
Damage pattern Cracks in the middle of several connecting links opposite the cutting links. Cause Chain is running with a worn sprocket. Chain tension is loose. Remedy Replace chain, sprocket and tire. If only one of these parts is replaced, it will wear out quickly under the influence of other worn parts.
Damage pattern Wear on the sliding surfaces of all links. Excessive wear of tire and chain sprocket. Result The saw chain is running irregularly, the chain is jammed and goes astray in the cut. Heavy pressure is required. Cause Dull or improperly sharpened saw chain and/or insufficient care of the guide bar. Remedy Change chain, chain sprocket and guide bar. If only one of these parts is replaced, it will wear out quickly under the influence of other worn parts.
1.3 Saw chain / depth limiter
Condition Shiny surface of entire depth stop. Result High pressure on chain when sawing. Very poor cutting performance. Cause Depth limiter distance too short. Remedy Spacing of depth stop machining to prescribed dimensions.
condition The front of the depth stop is shiny and/or worn. Result The chain is running rough and gets caught in the cut. Noticeable loss of performance. Cause Very large depth stop distance. Corrective action Grind cutting teeth to depth gauge prescribed. Tension the chain correctly.
Condition The depth stopper is too steep. Result Depth limiter sinks into the wood. Cutting performance is lost. Reason Incorrect depth stop machining. Remedy Shape the depth stopper to the correct shape. Resharpen tooth flap blades as well. If they are already too short, replace the chain.
Condition Front area has chamfered edges and has not been removed. Result Rough movement of the saw chain. Cause Incorrect processing of the depth stop. Corrective Action Correct the depth gauge.
Condition Depth stops vary in height or are not rectangular. Result Unquiet and rough chain movement. Cause Incorrect processing of depth limiter. Remedy Shape the depth stopper to the correct shape. Resharpen also the tine blades. If already too short, replace the chain.
Condition a The bar groove walls are uniformly worn to a minimum of the groove depth. Uneven wear on the groove wall. Result b Chain tips over, chain pulls away. Cause a Natural wear. b Improperly sharpened chain. Solution a Replace chain, chain sprocket and guide bar. If only one of these parts is replaced, it will wear out quickly. b Align the groove walls and resharpen the chain correctly. If the groove depth becomes too low, replace the cutter bar.
Condition Slotted walls are loose. Result Chain sits too loosely in groove, causes shifting of bar. High wear on sliding surfaces of cutting teeth and connecting links. Cause Application of an external force, e.g. in a jamming situation. Remedy Bend the groove walls. Danger of cracking!
Condition Tapered tire groove. Result Chain is jammed. Caused by external forces, e.g. if the cutting attachment is jammed in the cut. Remedy Widen the bar groove. Danger of cracking!
Condition The worn bar groove is in a wedge shape. Result Chain sits loosely in the groove, chain pulls back in the cut. Wear on the sliding surfaces of the cutting teeth and connecting links. Cause Natural wear and tear. Repair Change chain, tire, sprocket. If only one of these parts is replaced, it will wear out quickly again.
Condition Groove walls bent at the top and bottom at the end of the swivel area, underside of the guide bar wavy. The result is that the chain does not run smoothly. Continued use of a similar bar increases bar wear and the chain moves faster. Cause Chain tension is loose for a long time. Remedy Straighten slot walls. If the defects are already too great, replace the chain, bar, sprocket. If only one of these parts is replaced, it will wear out quickly again.
Condition Heavy wear on the tooth flanks and/or periphery. Cause In addition to normal wear (approx. the service life of two saw chains), shocks and chain runout cause premature tooth tip wear. Heavy chain slack or incorrect chain pitch causes heavy scoring on the tooth flanks and periphery of the chain sprockets. Repair Install a new, suitable sprocket.
Use of special tools
Experienced craftsmen recommend the use of profiled shortening equipment. This allows a quality job to be done, avoiding damage in the subsequent use of the tool.
Figure 1. Chainsaw rivet punches This is a mechanical tool that is similar to a conventional press. Anvil included, slots for clamping chains with different tooth pitch. For convenience, there are interchangeable tips for squeezing out the rivets. The tool is only intended for separating the links.
The riveting and splicing machine
Figure 2. Riveting and rolling machine Used together with a riveting and rolling machine for riveting and rolling saw chains at different pitch. Cutting depth of the side chains can vary between 1.1 and 2 mm. Included are rotating inserts, anvils marked A or B (difference in pitch).
Working mechanism. a saw chain with a new link and fresh rivets is attached to the guides. The section is then pressed against the built-in anvil with a roller, the motor is started. During rotation, it presses and crushes the rivet. During the process you need to slowly screw in the adjusting screw. Advantage of riveting-rolling machine. in quality and strength rivets do not differ from the factory ones, they can withstand higher loads.
Important! It is not practical to buy machines for the home workshop. They are priced high and are only for use with chainsaw heads.
Keyless tensioning system
It’s relatively new, if not cutting edge. Differs from the classic wrench, as follows:
A wing nut (swivel cap) with a knob for tightening by hand is used instead of a 13mm wrench nut on the cap. It also has a nut, but it is hidden inside. Instead of a screwdriver adjustment screw, in this system the tensioning is done with a tensioning wheel (adjusting knob).
Instead of a gear shaft, there is a sprocket and a tension washer.
- The mechanism itself is more complicated than a traditional wrench;
- the installation of the cutting set causes additional problems, t.к. makes it difficult to mate all the parts in the correct order;
- Smaller adjustment stroke, slightly stretched chain will still work in a traditional tensioning system, here it will sag and become unserviceable.
Only one advantage: no screwdriver or spanner needed, and adjustment and tightening can be done by hand. There is no positive feedback on this system. Negative, on the other hand, a large number. To those accustomed to traditional adjustments, the keyless system during assembly seems to be a technical puzzle.
Perhaps over time, the keyless system will prove its right to use. But it has so far gotten to the point where customers take their new chain saws back to the store and replace them with conventional ones, never having been able to figure out the assembly and the benefits of the new system.