No Drill Pulled From Punch

15th February 2020

For drilling holes in various materials, breaking walls, drilling rocks and roads, a perforator is designed. The tool is used under heavy loads and eventually malfunctions. You can replace the failed hammer with an inexpensive Chinese model. But if you have a branded tool, then throw it away with AL-KO. In order not to give half the cost of a punch for troubleshooting, you can do it yourself. Not a single repair is complete without studying the device structure and the procedure for disassembling it.

Types of rotary hammers

Hammers have several classifications. This is due to various areas of application of the tool.

The number of modes can be from one to three:

Drilling. The punch works in drill mode;

Hammer drilling. You can make holes in brick and concrete;

Jackhammer, that is, a blow without drilling.

Punch Drive Types:

Electric. Network connection or battery operation;

Rotary hammer with battery

Pneumatic. Such rotary hammers are used where the presence of electricity is dangerous due to fire or explosion. And in conditions of a large amount of water, where a short circuit may occur, for example, when eliminating the accident;

Petrol. The tool is used in the repair and construction of roads, mining. Mostly as a jackhammer.

Weight classification:

Lungs. 2-4 kg. Power 400–700 watts. Used in everyday life;

Medium. About 5 kg. Power 700–1200 watts. Professional

Heavy. Than 5 kg. Over 1200 watts. In construction.

Types of cartridges used in rotary hammers:

Sds is installed on light and medium perforators for working with drills up to 20 mm;

Sds max is used for drills over 20 mm, therefore they are installed on heavy perforators with high power.

Classification by engine location:

Simple or horizontal engine. Such rotary hammers have less weight and dimensions;

Barrel or vertical engine. Powerful rotary hammers.

Rotary hammer device

Regardless of the functions and designs, rotary hammers have similar basic elements.

Simple rotary hammer with network drive

Simple rotary hammer device

A barrel punch has the same basic components.

The device of a barrel punch with a network drive

The barrel punch has the same main components

The percussion hammer mechanism can be made in two versions:

Shock mechanism with a swinging bearing;

Swing Bearing Mechanism

Crank mechanism

A swinging bearing is also called drunk. Such a mechanism is used in light and medium perforators.

Impact drunk bearing mechanism

A crank mechanism is used in heavy rotary hammers.

Crank-hammer percussion mechanism

How to disassemble a punch

Disassemble the hammer drill in sequence. Inspect all parts carefully. Even if you are looking for a problem in one node, you can find damaged parts in other nodes. When disassembling the tool, clean the housing from dust and dirty grease.

How to disassemble a cartridge and pull out a stuck snap

Start by disassembling the cartridge so that it does not interfere with the removal of the gear housing.

Remove rubber boot 1, circlip 2 and plastic boot 3.

Ball groove bush

If a drill or other equipment is not pulled out of the cartridge, there are two options for solving this problem:

Grip the snap in a vice. Slightly staggering the punch, pull it towards you;
Grip the hammer with rubber gaskets to prevent damage to the plastic case. Clamp the end of the tool with a gas wrench. Use a hammer to tap on the key in the direction of the tool axis.

The second option is used as a last resort. If after several strokes the drill or chisel could not be pulled out, discontinue. You may damage the punch. Disassemble the chuck and gearbox. With a punch, try to knock out the snap. After this procedure, most likely, you need to replace the raster sleeve. To avoid further such a problem, lubricate the end of the tool.

How to remove a stuck drill from a drill chuck

How to remove the mode switch

In some models of rotary hammers, the switch is removed by turning to the extreme right position, in others. To the far left. Consider the extreme right position.

Put the mode switch on the beat. If there is no punch mode, a punch with drilling.

Shock switch

Pry the switch with a screwdriver

Analysis of the electric part of the punch

Unscrew and remove the back cover.
Turn off bolts of fastening of a power cord.
Remove the button and wires from their grooves.

Analysis of the mechanical part of the punch

Remove the plastic gear housing. You will see an aluminum case with a drunk bearing inserted into it, an intermediate shaft, a raster sleeve.

Raster sleeve and drunk bearing

Helical gear removal

Spur gear removal

The raster sleeve removed from the sleeve

Sleeve with a striker

How to assemble a hammer drill

Assembly is carried out in blocks. First, assemble the small parts into blocks, and then connect them.

Insert the ball bearing and sleeve into the aluminum gear housing.
Put elastic on the body. It prevents the flow of grease.
Connect the raster sleeve to the sleeve.
Lubricate the drunken bearing and gears liberally.

Gearbox after cleaning and lubrication

Hole in which to insert a screwdriver

Put on the back cover

Setting the mode switch

How to assemble a hammer drill

Punch Diagnostics

Take the multimeter, put it into dialing mode and start the test with the power cord.

Connect one probe to the end of the plug, the other to the pins on the other end of the wire. When connecting to one of the contacts there should be a sound signal. Do the same with the other end of the plug.
Check the power button on the contacts with the power cord and with the stator. Press the trigger button.
Check reverse contacts.
Connect the probes to the brushes to check contact through the anchor.
Connect the probes to the stator wires and ring them.
If the stator or brushes do not ring, and the buttons and power cord are working, go to the diagnostics of the collector and motor windings.

Diagnostics of wires and punch buttons with a multimeter

At the anchor, first inspect the collector and winding. If the wiring is melted, a burnt insulating varnish will leave black marks or a specific smell. You can see bent and wrinkled turns or conductive particles, for example, solder residues. These particles cause a short circuit between the turns. Collector Damage: Raised, worn, or burnt plates.

Diagnose with a multimeter:

Put a resistance of 200 ohms. Connect the test leads to two adjacent collector plates. If the resistance is the same between all adjacent plates, then the winding is working. If the resistance is less than 1 ohm and very close to zero, there is a short circuit between the turns. If the resistance is above the average two or more times, then there is a break in the turns of the winding. Sometimes, at a break, the resistance is so great that the device goes off scale. On an analog multimeter, the arrow will go all the way to the right. But on digital it will not show anything;

Checking the integrity of the armature winding

Determination of breakdown to mass. Put the maximum resistance on the scale of the device. Depending on the tester, it can be from 2 MΩ to 200 MΩ. Connect one probe to the shaft, and the other to each plate in turn. In the absence of faults, the resistance should be zero;

Do the same with the rotor. Connect one probe to the iron body of the rotor, and move the other along the plates.

Definitions of winding closure with rotor housing

An anchor can be saved if the balance is not disturbed. If during the operation of the device an intermittent hum is heard and there is a strong vibration, then this is an imbalance. Such an anchor must be replaced. And you can repair the winding and collector. Small short circuits are eliminated. If a significant part of the winding is damaged, it can be rewound. Worn and badly damaged lamellas to grind, grow or solder. In addition, do not undertake to repair the anchor if you are unsure of your capabilities. It is better to replace it or take it to a workshop for repair.

Checking the performance of the stator with a multimeter:

Set the resistance mode to 200 ohms. Connect the test leads to the ends of one winding. A unity means an open, and zero means a short circuit between the turns. If it shows a resistance of more than 1.5 ohms, then check the second winding. Both windings should have approximately the same resistance;

Check for a breakdown to ground, that is, the winding is shorted to the metal housing of the stator. In the multimeter, set the maximum resistance mode. Connect one probe to the end of the winding, the other probe to the metal housing of the stator. The unit indicates the absence of breakdown.

Faults and their causes

Frequent malfunctions of the punch:

Does not turn on. Check electrical circuit;
The punch does not hit. Breakdown in the percussion mechanism;
The tool does not twist, does not drill. Reasons: anchor bearings, anchor gear, gear;
The drill crashes, does not hold. Faulty cartridge or raster sleeve;
Sparking in the electrics enclosure. Reasons: violation of the insulation of the armature winding, wear of the brushes, collector, clogging of the brush holders;
Arcing in the area of the power button. Faulty button contacts or wires;
The punch is heated. The reason is worn out brushes, short circuits of windings, poor gear lubrication;
The hammer drill does not hold a cartridge. The snap ring or retainer was broken.

DIY repair

When disassembling the unit, carefully inspect the parts for cracks and chips.

Power Button Replacement

Before replacing, mark the wiring and contacts of the button so as not to confuse the connection procedure.

To replace the button, just unscrew the screws of the contacts. But there may be buttons without cogs. Here, near the contacts, there are holes in which a needle or thin awl is inserted. Poke in the hole, push and pull the wires. Do not pull the wire; you may damage the button.
The wires must be stripped and tinned.
Take the old button and buy a similar one.
On the new button, insert the awl into the hole, gently press and insert the wire. It will automatically snap into contacts.

Replacing a button with an awl

Brush replacement

Brushes must be checked periodically. When one is worn by 40%, change both. Also, clean the brush holders.

To remove the brushes, remove the back of the case. Fold back the springs that press the brushes.

Fold back the spring pressing brushes

Replacing and connecting the stator

Remove the stator from the electrics housing. Put a new one in its place.
Screw in the fixing bolts.
Install the air intake.
Proceed with connecting the windings. Connect the two ends of the different windings to each other and connect to the nearest brush. Connect the other two connected ends to the start button. Connect the wire from the second brush to the button.

Bearing replacement

There are several bearings in the hammer drill. To remove them, a puller is required. In some cases, it is necessary to remove the snap ring. If there is no puller, hang the shaft with the bearing and knock it out with a piece of wood. The bearing is planted using a tip from a polypropylene tube by tapping on it with a hammer.

Cartridge replacement

Cartridges in rotary hammers change very simply. Remove the rubber boot, snap ring, plastic boot, washer, pressing balls, retaining plates, spring. In different models, the number of rings and plates is different. Put a new kit in their place.

Drunk Bearing Repair

Prepare a flat head screwdriver, clean rags, and gear lubricant recommended in the instructions.

The bearing is held by the bracket. Disconnect it with a flat screwdriver.
Remove the drunk bearing from the aluminum gear housing.
Take out the needle bearing.
Remove the gear and spring.
Remove the plastic alignment from the spring.
Replace defective parts.
Take the aluminum gear case and clean it thoroughly with a dry cloth. Clean all parts too.
Lubricate the bearing from the inside. Insert the needle bearing into it and also lubricate.
Insert the gear, lubricate from the inside and insert the spring into it. Put on the centering.
Lubricate the intermediate shaft and place the shift bracket on it. Install the shaft in a drunk bearing.

Drunk Bearing Assembly

Drunk bearing with sleeve

Repair raster bush and shock bolt

To disassemble the raster sleeve, it is necessary to compress the spring, remove the circlip and gear.

Raster sleeve assembly and without gear

The impact bolt is repaired by replacing parts or changes completely if it falls apart.

There are holes in the raster sleeve on both sides, in which the retaining ring is clearly visible. Pry off and slide the ring on both sides with a small flat-blade screwdriver.

Impact Defect

Sleeve Replacement

The sleeve wears out less often than the raster sleeve, but with frequent overheating of the tool, it also fails. Remove the raster bushing and sleeve from the aluminum gear housing. Put a new one in its place.

Worn and new brisk sleeve

Features of repair of a keg

Repair barrel drills has the same principles as simple. The main difference in the design and the number of elements.

Brush replacement

Remove the bottom cover of the case and see the plugs that need to be unscrewed.

Source

Drill drill, pulled, punch