Circular saw: repair, characteristics, making a circular saw with your own hands. Repair of circular saws How to remove the armature of a circular saw interskol

Due to active use, equipment often needs repairs. However, circular saws may require repairs even under moderate workloads. In the process of using and servicing circular saws, popularly called circular saws, you should take into account some of the nuances of their functioning, be able to diagnose and, if possible, fix problems.

If the saw has lost power, started to jam and stop, these are clear symptoms of its failure. Additional signs indicating a malfunction of the device include engine overheating, difficulty starting, smoke or a burning smell, and sparking inside. In all these cases, the instrument must be immediately taken out of service and sent for diagnostics. In order to repair a circular saw, they usually turn to the services of craftsmen, but there are ways to deal with the breakdown yourself.

Main problems and their causes

A circular saw is a very convenient and practical tool that allows you to implement a lot of ways to process wood. With its help, you can cut boards lengthwise and crosswise, without restrictions on sizes and distances, make slats, and remove excess material piece by piece. Such a device is indispensable when working at heights, in cramped and hard-to-reach places where large and stationary analogs are powerless.

Like any electrical devices, such saws vary in quality and permissible operating intensity. Experts distinguish two main classes: industrial and household. An industrial circular saw is designed for operation under conditions of prolonged intense load, while a household one is considered a low-quality tool for which failure is common.

It is the latter type of device that you most often have to deal with when working at home. Household saws are designed for occasional short-term use, but even this does not save them from frequent breakdowns. These power tools generally do not have power regulators, safety devices or fuses. There is only a power button.

Such a tool is especially vulnerable to various malfunctions and can break at any time. The main reasons why this can happen:

• short circuit;
• careless handling;
• strong pressure;
• working with a dull saw blade;
• using the tool for purposes other than its intended purpose.

Diagnosis and elimination of simple defects

First of all, when repairing circular saws, it is recommended to use an LATR (adjustable laboratory autotransformer), designed for a load of at least 9 A and equipped with a built-in linear ammeter and voltmeter. For safety reasons, LATR should be connected to the electrical network through an isolation transformer with a transfer ratio of 1:1. These measures will help eliminate possible damage to electrical wiring and interference in the network due to short circuits and handling errors of the unit.

Repairing a circular saw begins with determining the nature of the malfunction. This could be mechanical damage or the failure of an electrical component. Failure localization is carried out based on certain signs. For example, smoke with a sharp burnt smell comes from inside the instrument; during operation, unusual sounds, noise and whistling are heard.

However, sometimes the saw does not work at all. No sounds, no smell - it doesn't turn on. Paradoxically, this case is the most optimistic, since the reason for this inoperability may be a banal violation of the integrity of the power cord or a break in its contacts. Therefore, the first thing we do is check the supply wires for breaks.

If everything is in order with the cord, there is still no need to rush to disassemble the device. Before doing this, it is better to check the contact brushes. These are elements of the so-called sliding contact, which are designed to supply current to the moving rotating elements of electrical devices. They are several small blocks of special conductive material (coal or graphite) that rest directly on the commutator (the rotor part of the electric motor).

Due to the constant rotation of the commutator, the brushes wear out greatly, rubbing against moving surfaces. After some time of use, they wear down to the point that they can simply “hover” over the contact pads, not reaching them. In addition, sometimes there is a loss of contact at the junction of the brushes and the stator terminals. All this should be checked and corrected regularly, for which most tools have a special casing or cover with easily unscrewed bolts.

Checking internal parts

Disassembling a circular saw is a rather complex process, and it is individual for each individual device. However, if everything is in order with the cord and brushes, and the device still does not work, disassembling the case is inevitable.

The body of most such electrical appliances consists of two fastened halves with a longitudinal seam between them. Having removed the disk and unscrewed the bolts and other fasteners, carefully open the shell, trying not to damage the internal elements and not lead to even more serious damage.

Regardless of the brand and build quality, one of the most vulnerable points of such units is the power button. Its malfunction is a very common cause of performance problems.

For most models, this button is usually located in the handle of the device. By unscrewing and disconnecting the housing, you can gain direct access to it. We check the serviceability of the switch using a tester. If the contact does not close when pressed, replace the button.

Repair of engine components

At this stage, it is worth remembering how the circular saw behaved when it broke down, and what signs accompanied it. Mechanical damage is almost always accompanied by the appearance of extraneous noise: whistling, crackling, grinding, etc. In this case, the first thing we try is to turn the motor shaft: it should rotate evenly and not too tightly, without jamming or vibration.

If any violations are observed, we disassemble the engine and carefully inspect the bearings in the housing and on the rotor: in all likelihood, one of them is to blame. Another possible defect is wear of the gear teeth of the gearbox. Broken parts must be replaced. It should be borne in mind that some operations, for example, removing the bearing from the motor armature, should not be performed independently, but it is better to contact a specialist with special equipment.

Rotor and stator failure is a common problem. Its main signs are strong sparking and smoke in the brush compartment, accompanied by a characteristic odor. If, when disassembling the tool, very noticeable traces of burning are revealed, it is necessary to replace all burnt parts with new ones. In the same case, when the armature looks undamaged, but there is a layer of soot on the stator, you should not rush to change the stator, since the problem may also lie in the rotor (not even in the rotor itself, but in its windings, where a wire break could occur).

It is not difficult to check the armature for a break: to do this, we disconnect the stator contacts from the graphite brushes and fasten the tester probes so that they contact the motor windings through the brushes. The tester should show slight resistance. Then we begin to slowly rotate the motor shaft, without stopping to monitor the readings of the device. At some point, the resistance may increase sharply: this will mean that the armature is broken and must be replaced.

Conclusion on the topic

A circular saw is a faithful assistant when processing and cutting wooden materials. We looked at all the practical ways to fix it at home.

However, many breakdowns can be avoided if you follow the basic operating rules specified in the instructions for each device.

You are usually allowed to use the saw no more than a few hours a day, with mandatory breaks. You should also only work with well-sharpened sharp discs.

A circular saw is an indispensable tool when building a house and running a farm. Even if all rules and regulations for use are observed, the saw, like any mechanism, can fail. To fix a malfunction yourself, you need to know how the tool works and how to correctly diagnose a broken part.

Electric circular saw device

A circular saw is not fundamentally different in design from other electrical appliances (household or construction tools).

Its main parts are:

The main difference between the saw and other tools is the presence of a sawing disk, to which torque is transmitted from the electric motor when the power button is pressed.

Spare parts for circular saw

Handheld Circular Saw Anchor

The armature is a copper winding that conducts current, and a magnetic circuit in which the rotation shaft is installed. On one side of the armature there is a gear, and on the other there is a manifold with lamellas. The magnetic core consists of plates and grooves insulated from each other and coated with varnish.

Circular saw rotor

The rotor is a steel shaft on which there is a core with machined, equidistant grooves in which the armature winding is laid.

Stator for circular saw

The stator is made of electrical steel with a high magnetic permeability coefficient. This element is rigidly fixed in the saw body. It has the shape of a cylinder with grooves into which the stator windings are placed.

Electric motor for circular saw

In most cases, commutator-type electric motors are installed on wood circular saws. It includes the above elements: armature, rotor, stator.

Circular saw shaft

The shaft is a metal rod that transmits torque from the motor to the saw blade flange using bearings.

DIY circular saw repair Interskol

Tool repair begins with determining the cause of the breakdown. If smoke comes out of the tool during operation, this indicates engine failure. If noise or whistling appears when the saw is operating, this indicates a mechanical malfunction.

There are times when the tool simply does not turn on without any signs of failure. In this case, first of all, you need to check the integrity of the wire supplying electricity and the contact brushes. Because the brushes supply current to the moving parts, they are susceptible to wear and over time can wear out to the point that the saw will not function. It happens that the contact of the brushes with the stator terminals is broken or oxidized.

Interesting! More than half of the cases when the tool does not turn on are due to malfunctions of the brushes, so manufacturers provide special covers that can be easily unscrewed and the brushes checked without completely disassembling the tool.

To repair the electric motor, it is necessary to disassemble the tool. This must be done sequentially, remembering the order of the removed parts. You can prepare a wiring diagram for the electric saw. This is necessary for subsequent correct assembly.
As a rule, engine breakdowns are associated with manifold problems. Removing it is not so easy. This must be done safely for the armature bearing. You need to use a sharp tool. Having inserted it into a special recess, you need to carefully tap it with a hammer until the shaft moves.

Then the anchor is removed, from which the carbon deposits are removed. If it is severely worn, a complete replacement of the spare part is required. After this, the contacts of the collector windings are cleaned, and if necessary, they are changed.

In order to avoid failure of your tool, you should carefully handle, transport and store it. Most breakdowns occur as a result of working with a dull saw blade or lack of lubrication in the parts, and this leads to overload of all elements of the saw and equipment failure.

The benefits of any home tool can only be fully appreciated after it fails. This axiom is known to every home handyman. The presence of a large number of devices in the arsenal has led to the fact that most people simply cannot imagine how to perform this or that operation without them.

A circular saw is used for smooth cutting of various materials.

In the case of a circular saw, this is especially true. The fact is that it is indispensable for longitudinal sawing of wood; it has no worthy analogue among hand tools. You can't do this with a regular hand saw. Therefore, when the circular machine refuses to work for some reason, all work stops. Something needs to be done urgently. However, do not rush to take it to the workshop; it is quite possible to repair a circular saw yourself.

Fault localization

The first thing you do is try to determine what is broken. This does not mean a specific node, but the nature of the damage. It can be mechanical or occur in the electrical part of the saw. In other words, if smoke comes out of it, this is one thing, but when extraneous noise or whistling appears, this is completely different. It is these two criteria that are the main ones when localizing a fault. There is, however, a third one, when the saw makes no sounds at all. Let's start with it.

Oddly enough, the fact that the saw is silent can be a good sign. Here it would be useful to mention those malfunctions that are usually printed on the last page of the instruction manual. At first glance they seem funny, but show them a little respect. Check if there is voltage at the outlet and if the power cord is working properly. If everything is fine, then there is only one chance left to avoid complete disassembly - check the brushes.

On the vast majority of circular saws, in order to get to the brushes, you need to unscrew two bolts. This unit consists of two carbon elements that rest against the collector. Since it constantly rotates, the brushes are subject to wear and over time “freeze”, i.e. can't reach him. This is what you need to pay attention to first. In addition, the carbon brushes are connected to the stator terminals. Sometimes contact is lost at this point. Check it. If everything is fine, disassembly cannot be avoided.

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Disassembly and its features

The operation itself is quite complicated; some workshops charge money for it regardless of the result of the repair. Each saw has its own device, and it is impossible to give exact advice. You can figure this out on your own. But let’s take a closer look at what to disassemble first.

A very common problem, regardless of brand, is a faulty switch button.

For all models it is located in the handle, which, when untwisted, splits into two parts.

You can’t completely halve it, it will stick to other parts, but you will be able to get to the button, but it will be a little inconvenient. Despite this, it is necessary to check the functionality of the switch using the tester probes.

If it turns out to be faulty, the repair is complete. However, to put a new one in place, the saw will have to be completely disassembled. But if the button is working, you will have to do this too.

Remove the disc. There is an opportunity to remove the protection, which is what you do. There are 4 long bolts under it, unscrew them. The sequence and number of parts may be slightly different, but in the end you should have a motor with a gearbox, a handle and an electrical cord in your hands. You disconnect the gearbox, and now it’s time to remember how the malfunction manifested itself.

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Mechanical problems

Symptoms of such malfunctions can manifest themselves in different ways, but almost always the operation is accompanied by extraneous noise. This may be a whistling, grinding or clicking sound. Now, while the engine and gearbox are still assembled, it is necessary to determine which of them is faulty. Try turning the motor by the shaft. It should rotate quite hard, but evenly, i.e. should not jam.

If the motor shaft does not rotate or rotates jerkily, the motor is faulty. Take it apart and look at the bearings. The first is located in the engine housing, the other on its rotor. We can assume with complete confidence that one of them is to blame. The first one would be good, it's quite easy to change.

If the bearing on the engine armature is at fault, you can safely take it in for repairs. It is almost impossible to remove it yourself without a special device. In addition, any attempts to do this may result in damage to the anchor. You will not have to carry the entire saw to the workshop, but only the rotor. It's easier and cheaper.

The main gearbox malfunction is wear of the gear teeth. In this case, it must be replaced. You should also pay attention to the armature splines. They should also not be damaged.

The reasons for the breakdown can be very different. Manufacturers recommend that you first conduct a thorough inspection of the tool and try to visually determine the malfunction. If this does not give any result, then you need to start disassembling. The device of a circular saw is quite complex; the main task is to get to the collector, because the main problems arise with it.

The manifold needs to be removed, but it is not that easy. This must be done safely for the armature bearing, and carefully separate the motor armature from this bearing. To do this, you need to use a pointed tool, which is inserted into a special recess in the middle of the motor shaft. Having inserted it into the recess, you should hit the tool with a hammer until the shaft moves.

The anchor is removed and cleaned of carbon deposits, and changed if necessary. Next, the contacts of the collector windings are cleaned. It is also necessary to check their inductance with an ohmmeter, and if faults are found, the contacts are changed. Often the breakdown is due to high friction between the cheek and its holder, which leads to jamming. If this is the cause of the breakdown, then the cheeks must be installed strictly perpendicular to the holders.

Important! If you do not have repair experience, then it is better to take the tool to a workshop, otherwise you may worsen the situation.

These problems are easy to troubleshoot and can be fixed on your own. However, do not forget that instruments under warranty are strictly prohibited from opening, otherwise the warranty on them will be void. Therefore, saws under warranty should be taken to specialized centers.

A sharp disc as a means to avoid repairs

In many ways, the quality and reliability of a circular saw depends on the ability to sharpen the blade. A poorly sharpened saw leads to increased load on the tool, which reduces its service life. Signs of disc wear are: the need to exert great effort when working, burning of the edges of the cut, strong heating of the protective casing. Sharpening circular saws starts from the back surface directly on the machine.

Before starting, you should mark the tooth from which sharpening will begin. When sharpening the first tooth, you need to remember the number of movements, because the remaining teeth should be processed exactly the same amount. If the disk is removed from the machine, it is clamped in a vice using wooden blocks.

The disc should be rotated as you sharpen. After completing the work, the disk is installed on the machine and a test cut of the unnecessary bar is carried out. If there is strong noise and uneven material flow, then it is necessary to check the height of the teeth. If there are protruding teeth, they should be filed down to the general level.

Note! Precise sharpening is only possible on special machines.

The best repair for circular saws is no repair.

It should be noted that improper operation of a circular saw greatly affects its service life and leads to an immediate need for repairs. Even knowing how to sharpen a circular saw will not protect it from improper use. Let's look at how to use a circular saw so that its repairs have to be done as rarely as possible:

• It is necessary to use only those blades that are suitable for this saw model;
• All discs must be sharp, as dull ones lead to engine overheating;
• You should always check that the disc is installed correctly and that the clamp is tight;
• Do not allow the motor to overheat under any circumstances.

By adhering to these simple rules, you can protect your instrument from damage as much as possible. Remember that following operating instructions costs much less than the necessary repairs if a circular saw breaks down. Important! When working with a circular saw, you must carefully follow safety rules.

The armature of a commutator motor of a power tool may fail due to overcurrent. This occurs when the cutting tool becomes skewed and the armature rotation speed sharply decreases when the power supply is turned on. At this moment, the reactive component of the supply current to the armature windings sharply decreases, providing the rated current consumption and rated power under normal operating conditions of the power tool.
An increase in the share of the active component of the current consumption of a power tool against the background of a sharp decrease in the complex resistance of the armature windings at the time of overload leads to a sharp increase in the current consumption of a power tool, significantly exceeding the rated current consumption, which in turn leads to sparking of the brushes and overheating of the commutator, burning and charring of the insulating layer between the lamellas of the electric motor commutator and - ultimately - to a short circuit of the commutator and a decrease in the torque of the electric motor.
For circular saws, a similar situation is possible when you are in a hurry when sawing raw boards, for example, and the saw is skewed; naturally, normal sawing requires compliance with all safety measures provided for in the instructions for the tool and caution when working.
But, if it does happen, the saw needs to be repaired.
Repairing a saw requires replacing the anchor; to do this, you need to disassemble the saw, remove the burnt anchor and put a new one in its place.

First, remove the saw and the safety guard; to remove the lock washer you will have to use a special tool or get creative,

To remove the lock washer, I used a drill, a rivet and bent pliers.

Next, remove the collector casing and the handle, thus freeing access to the worm gearbox

We remove the gearbox, unscrew the bolts securing the main bearing flange

bend the insulating gasket of the handle from the body, remove the brushes

and pull it out by the main bearing flange - the burnt anchor, here it is, in all its glory

Next, we alternately knock the bearings off the armature shaft from the side of the commutator and the worm. For these purposes, it is better to use a puller, but if you don’t have one at hand, you can take, for example, a powerful wrench, hold it in a vice and tap the end of the armature shaft to knock it off, seated on him, bearing. In the same way, but with emphasis on the protrusions of the main bearing flange, the main bearing is knocked down.

After removing the bearings from the burnt armature, they can also be placed on a new armature by lightly tapping the end of the bearing, gradually pulling the bearing onto the armature shaft; do the same with the second bearing. Assembling the saw, but with a new anchor, occurs in the reverse order. We wish you success, do not rush during assembly, so as not to touch the armature with something sharp and hard and damage the windings and commutator of the new armature.

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