How to Assemble a Metabo Rotary Hammer Reducer
A properly working hammer drill is an excellent assistant in the household and in production. This versatile tool with many functions allows you to comfortably solve even the most complex tasks. If the punch is broken, it is not necessary to immediately carry it in for repair. A home foreman can independently disassemble and repair this tool. How to repair a punch do it yourself?
Perforator device and its mechanism
Unlike a drill, as well as an impact drill, a rotary hammer has an enhanced impact function, which puts it an order of magnitude higher in situations where it is necessary to use significant mechanical stress on the processed materials.
This is achieved by the design features of the punch device. The device is equipped with an independent mechanism for generating a powerful pneumatic push of the working tool, and this ability relieves the master from the use of physical effort when drilling and chiselling concrete and stone.
Sectional percussion hammer mechanism
The conversion of the rotational motion of the electric motor into the translational oscillation of the shock mechanism is carried out by creating compression between the pistons. This movement is transmitted to the drummer. The striker made of high-strength steel, in turn, sends the energy of compressed air directly to the working tool. a drill, chisel or blade. Such a device unit allows you to increase the impact power to a huge destructive force. 20 kJ.
Depending on the location of the engine, drill-shaped and barrel-shaped types of perforators are distinguished.
- The first type of device is similar to a drill, in which the motor is located in the same axis as the drill.
- In rotary hammers of the second type, the motor is mounted perpendicular to the axis of drilling.
Barrel perforators differ in large dimensions, but at the same time have a more advanced cooling system, which allows the tool to be used for a long time without stops. Devices in the form of a drill are much more compact, they are convenient when working in cramped circumstances, when access to the object is limited.
Hole Punch Diagnostics
If during operation, malfunctions in the operation of the rotary hammer become apparent, disconnect it from the power supply and conduct an external inspection. If no external signs of damage are found, you will have to disassemble the case and look for the problem inside.
One of the reasons for the failure of the device is a break in the power cord. In this case, the punch motor does not turn on. For its diagnosis, it is necessary to carefully inspect the cable connecting the tool to the network. It must not be damaged, broken or melted. A working power cord remains cold during operation. If the wire is not in order, it should be replaced with an equivalent one. The cross section of the conductive elements must correspond to the power consumed by the tool.
A multimeter is recommended for testing electrical circuits. Using this device, you can not only detect a power failure, but also “ring” the motor winding coils, determine the presence of voltage on the start button.
Conventionally, all punch malfunctions can be divided into two categories. mechanical and electrical.
Malfunctions in the mechanical part: the crown cannot be pulled out of the barrel, the drill does not hammer, the drill does not rotate and others
The mechanical category of malfunctions includes malfunctions that occur when the engine is running:
- the drill does not hammer;
- the drill does not rotate;
- the crown is not pulled out of the trunk (jammed);
- the chisel does not hold in the cartridge (pops up);
- extraneous sounds are heard inside the mechanism, rattle, vibration.
Failures in the electrician: the motor does not rotate, spark brushes on the collector and other types of breakdowns
The following symptoms indicate problems with the electrical part of the punch:
- the motor does not rotate when turned on;
- brushes sparkly on the collector;
- the smell of burning insulation emanates from the body;
- caustic smoke comes out of the tool during operation.
In order to find out and eliminate the cause of all these phenomena, the hammer must be disassembled.
The procedure for disassembling and assembling the device
You should only start disassembling yourself if you have the proper tools and equipment. To repair the puncher with your own hands you will need:
- screwdrivers with different slots;
- wrenches and socket (hex) wrenches;
- pullers for bearings.
In addition, replacement parts, rubber seals and gaskets will be needed. To lubricate the gears of the mechanisms you will need:
- cleaning solvent.
In case of self-repair of an electric motor, in addition to a multimeter, you will need:
- spare carbon (or graphite) brushes;
- copper wire of the required section;
- rewind pattern.
Disassembly of the punch begins with the removal of the cartridge. As a rule, this is an SDS-plus system cartridge, which is disassembled with a flat-head screwdriver. In this case, the cartridge should not have a drill or a chisel.
There are times when the drill sticks and it is not so easy to get it. Then you need to gently knock the cartridge around with a rubber mallet and pour a few drops of WD-40 type grease inside. After a few minutes, try again, the drill should be easily removed. After this, you can begin to disassemble the cartridge itself. Procedure:
- Pull the plastic skirt down.
- Use a screwdriver to remove the rubber protective boot.
- Release and remove the snap ring located behind the boot.
- Remove the plastic boot, spring, retaining plates and balls.
- Clean all parts from old grease and put in a clean place.
Video: how to remove a drill stuck in a cartridge
Mode switch dismantle
To remove the mode switch, you must:
- Turn the toggle switch to the “strike” position (the icon with the image of a hammer) and turn it about 1 cm lower.
- Release the lever from the socket.
- Pull the lever towards you.
How to check the start button and brushes
To get to the collector brushes and start control buttons, you need to remove the back cover. For this, two or three screws are unscrewed (depending on the model) from the plastic case.
If the cause of the malfunction was due to the wear of the brushes, you can eliminate it by installing a new pair. The working length of the brush must be at least 8 mm. The rubbing surface. without traces of scale or chips.
The start button is checked with a multimeter. It must be remembered that the engine speed control system is also located inside the trigger. If melted plastic is visible on the button body, it should be replaced entirely, since it will no longer function properly.
Attention! It is strictly forbidden to check the operation of the button when the tool is connected to the network!
After replacing the button, it is necessary to replace the housing cover, do not forget to tighten the screws securely. Only then can the perforator work.
How to disassemble an electric motor
To disassemble the electric motor, it is necessary to disconnect the motor housing from the gearbox. Between themselves they are fastened with four screw screws. If you unscrew them, the mechanical part is easily separated from the plastic casing. When disassembling, the rotor of the motor is removed from the guide sleeve, freeing up access to the gearbox. Accordingly, it becomes possible to examine the electrical components of the engine.
Video: How to Assemble a Metabo Rotary Hammer Reducer
The motor consists of a movable rotor and a rigidly fixed stator. The rotor rotates under the action of an electromotive force arising on the windings, consisting of turns of a copper conductor. Inspection of the windings is to determine the integrity of the insulation, the absence of a short circuit between the turns. This is done with a multimeter by successive measurements of resistance on the lamellas. In the event of an interturn short circuit, the anchor must be replaced or repaired. Stator windings can be rewound independently at home using a special template.
The anchor, as a rule, changes as a whole, together with bearings and an air intake plate.
How to disassemble and check the gearbox: how to remove the plastic case, remove the “drunken bearing” and other elements
In order to determine the malfunction of the gearbox, it must be completely disassembled. To do this, the plastic case is removed, the gearbox is thoroughly cleaned of old grease. From the gear case are disconnected:
- floating bearing;
- drive gear shaft;
- raster sleeve;
- sleeve with a piston.
The floating bearing, also referred to as the “drunk bearing”, is mounted in the aluminum gear housing with a staple, which must be pressed with a flat screwdriver. The released bearing is removed and replaced if necessary. In addition, you should pay attention to the fact that inside the "drunken bearing" is a needle bearing on which the drive gear rotates. When the hammer is in impact mode, it experiences heavy loads, and therefore often fails. The new bearing is purchased separately or assembled with a gap.
The raster sleeve contains an impact bolt, which is mounted inside with a metal retaining ring. On the sides of the sleeve there are two technological holes through which access to the locking mechanism. After the ring is removed, the impact bolt freely falls out of the sleeve. Inside it is located directly the drummer made of high alloy steel.
When repairing or replacing an impact bolt, it is also necessary to replace the rubber sealing bushings, which ensure the tightness of the mechanism. All parts of the hammer are subject to heavy lubrication with special grease.
In the plastic casing of the gearbox at the output of the raster sleeve there is another needle bearing, which must be well lubricated.
Video: how to fix a punch and replace an impact bolt
Possible malfunctions, causes and solutions
To repair the punch with your own hands, you must first determine the external manifestations of malfunctions.
The punch does not hit
If the puncher stopped beating when switching to impact mode, but the drill rotates, it is most likely that the floating bearing is damaged. The solution will be to replace it with a new one.
The second possible reason is the disruption of the shock mechanism. Often during overloads in work, the steel hammer strikes, this first leads to a weakening of the impact, and then to its complete absence. The striker must be replaced.
The third probable cause is wear or damage to the piston group of the perforator. The sleeve and piston should be replaced.
The rotary hammer does not spin or drill
If the chuck does not rotate when you press the start button, the cause can be determined by sound. If the electric motor is buzzing, but does not turn the cartridge, most likely, something does not allow the rotor to rotate inside the gearbox. What happened to the engine will have to figure out by disassembling the mechanical part of the tool.
If the engine does not hum when turned on, it is more likely that the motor has failed. Opening the lid of the device, it is necessary to determine what exactly led to this phenomenon. This can be an open circuit, a breakdown of the start button or a short circuit in the coil windings. With the help of a tester, a specific reason is determined and appropriate repairs are made.
The drill does not hold in the cartridge and flies out
Incontinence of tool accessories can occur during continuous operation. The drill or chisel inserted into the cartridge does not hold and flies out during operation. With such a tool it is not only impossible to continue chiselling, it is also very dangerous. a chisel that has flown out can cause injury.
The reason for tool incontinence lies in the wear or breakage of the cartridge. The cartridge must be disassembled and determined what the problem is. The balls may have deformed, a workout has appeared on the restrictive ring, or a fixing spring has slipped. Usually, after replacing a damaged part, the cartridge starts functioning normally again.
Video: why drills fly out of a punch
Brush sparking is a fairly common occurrence when using the tool in dusty environments. As a rule, sparking is a consequence of the development of the material of the brushes themselves. Replacing the situation with new ones will help to correct the situation; sparks will no longer fly out.
If not, the cause must be sought in the stator or rotor windings. It is possible that a large amount of dust penetrating the engine abrased the protective varnish covering the copper conductors. And this entails a short circuit. The presence of inter-turn circuit is checked by electrical devices (multimeter).
Preventative maintenance of the tool: replacing the brushes, lubricating the bearings of the rotor working shaft and additional varnishing of the windings on the coils will reduce the likelihood of breakage.
In addition, it should be borne in mind that dust can adhere to the grease of the bearing located near the collector. To prevent this, the collector is degreased with a swab dipped in alcohol or solvent.
The puncher is very hot
If the rotary hammer overheats during operation, this is a clear sign of a malfunction in the normal operation of the electric motor. First of all, to prevent overheating, the operating mode of the device must be observed:
- pause at regular intervals;
- after loading give the tool the opportunity to idle.
When drilling, it is recommended to use a periodic mode: apply maximum power no more than 1 minute, then turn on idle for 3-4 seconds.
If the case temperature does not decrease, then it is necessary to revise the electric motor. Having felt a characteristic odor from under the instrument cover, you must immediately stop working and disconnect the device from the network. It can be disassembled only after complete cooling.
The hammer does not hold a cartridge
Sometimes there is a situation when a cartridge flies with a snap on a working punch. This is due to wear on the holder housing of the cartridge at the end of the raster sleeve, which is a snap ring. When it breaks, the fixation is broken and during the push a rubber boot flies, followed by a spring and balls.
You can restore the cartridge to normal operation by installing a new retaining ring. This is done quickly and does not require any additional devices other than a conventional screwdriver.
Replacing the main components of the hammer drill
The replacement of key elements is best done before the part becomes worthless. This will protect the tool from more severe damage, the correction of which will cost more and take more time. Most often you have to perform a replacement:
How to change bearings
If during a routine inspection the grease is visible on the bearing, it cracks or crunches when scrolling by hand, this means that it is time to replace it. Dismantling of the bearing is carried out using a special puller, consisting of a screw part and a device for gripping the housing of the bearing sleeve. Tightening the thread creates a force that removes the bearing from the shaft.
The installation of a new bearing at the workplace is carried out with a rubber or wooden hammer. When installing, it is important to prevent the bearing axis from skewing about the shaft axis. Lubricate the part after installation.
How the start button changes
To replace the start button, you must remove the cover that covers the electrical equipment of the punch. Then you should disconnect the contacts of the conductors connected to it and pull out the button housing from the seat. In this place, install a new button, connect the contacts and assemble everything in the reverse order.
How to remove and change brushes
The replacement of the carbon brushes of the collector is carried out by an electric screwdriver. If you unscrew the lid, access to the brushes will appear. Each part is removed in turn from the nests of the brush holder. In some models, the device of the clamping mechanism differs, as a rule, this is a spiral spring, which must be removed during replacement.
Attention! Before replacing the brushes, the hammer must be disconnected from the power supply.
How to replace a cartridge
In most cases, the cartridge can be repaired. If the wear of individual parts has exceeded the permissible limits or the rubber boot and the plastic skirt are damaged, it is advisable to change the cartridge as a whole.
The procedure for replacing the cartridge is clear from the above procedure for disassembling the punch.
Features in the repair of barrel drills
All the described procedures for assembling and disassembling the mechanisms of perforators are true for its barrel version. However, there are several nuances that must be considered when repairing it. The vertical arrangement of the engine at right angles to the impact mechanism somewhat changes the disassembly order. So, to gain access to the gearbox and piston, it is necessary to remove the plastic cover located in the upper part of the tool case. This facilitates the repair of the mechanical part of the device if the shock function suddenly disappears.
Access to the electrical part of such a perforator is carried out after removing the lower casing. And the replacement of the brushes is simplified, since there are holes on the sides of the glass through which they can be easily removed.
It should be noted that many professional barrel drills do not have a drilling mode. Since their purpose is mainly to drill and chisel heavy concrete surfaces, they are equipped with an SDS-max cartridge with an 18 mm shank. There is no fundamental difference in the design of the SDS-plus cartridge, but the dimensions differ markedly. L-shaped punchers are recognized as more reliable in operation and belong to the rank of a professional tool.
Routine Care and Storage
In order for the tool to serve for a long time and in good condition, you need to follow simple rules.
- Before starting work, conduct a quick inspection of the technical condition of the tool. In no case do not ignore the signs of a malfunction, if any.
- At the end of work, clean the hammer from dust and debris. It is advisable to blow a stream of air from the vacuum cleaner.
- When transporting in the cold season, before starting work, give the device at least 20 minutes to “acclimatize” the device. The grease should thaw and become elastic.
- Work in compliance with the operating standards described in the technical data sheet of the tool.
Store the hammer in a dry and warm place. For long-term preservation, it is recommended to pack in a plastic bag and a cardboard box. Prevent moisture from entering electrical parts, including condensate from the air.
Aware. means armed. Knowing the intricacies of the device of the mechanism of perforators, you can repair the tool yourself and in the shortest possible time. However, if you timely look under the casing of the punch, clean and lubricate the mechanisms, then it is quite possible that you will not have to resort to repair at all. Regular maintenance of the instrument will help extend its life.