Bosch GWS 12V-76 Professional Cordless Angle Grinder Instruction Manual

GWS 12V-76 Professional
HEAVY-DUTY
Original instructions

Safety Notes

General Power Tool Safety Warnings 

WARNING Read all safety warnings and all instructions. Failure to follow the warnings and instructions may result in electric shock, fire, and/or serious injury. 
Save all warnings and instructions for future reference. 

The term “power tool” in the warnings refers to your mains-operated (corded) power tool or battery-operated (cordless) power tool.
Work area safety

•  Keep work area clean and well-lit. Cluttered or dark areas invite accidents.
• Do not operate power tools in explosive atmospheres, such as in the presence of flammable liquids, gases, or dust. Power tools create sparks that may ignite dust or fumes.
• Keep children and bystanders away while operating a power tool. Distractions can cause you to lose control.

Electrical safety

• Power tool plugs must match the outlet. Never modify the plug in any way. Do not use any adapter plugs with earthed (grounded) power tools. Unmodified plugs and matching outlets will reduce the risk of electric shock.
• Avoid body contact with earthed or grounded surfaces, such as pipes, radiators, ranges, and refrigerators. There is an increased risk of electric shock if your body is earthed or grounded.
• Do not expose power tools to rain or wet conditions. Water entering a power tool will increase the risk of electric shock.
• Do not abuse the cord. Never use the cord for carrying, pulling, or unplugging the power tool. Keep cord away from heat, oil, sharp edges, and moving parts. Damaged or entangled cords increase the risk of electric shock.
• When operating a power tool outdoors, use an extension cord suitable for outdoor use. The use of a cord suitable for outdoor use reduces the risk of electric shock.
• If operating a power tool in a damp location is unavoidable, use a residual current device (RCD) protected supply. The use of an RCD reduces the risk of electric shock.

Personal safety 

• Stay alert, watch what you are doing, and use common sense when operating a power tool. Do not use a power tool while you are tired or under the influence of drugs, alcohol, or medication. A moment of inattention while operating power tools may result in serious personal injury.
• Use personal protective equipment. Always wear eye protection. Protective equipment such as dust masks, non-skid safety shoes, hard hats, or hearing protection used for appropriate conditions will reduce personal injuries.
• Prevent unintentional starting. Ensure the switch is in the off-position before connecting to a power source and/or battery pack, picking up or carrying the tool. Carrying power tools with your finger on the switch or energizing power tools that have the switch on invites accidents.
• Remove any adjusting key or wrench before turning the power tool on. A wrench or a key left attached to a rotating part of the power tool may result in personal injury.
• Do not overreach. Keep proper footing and balance at all times. This enables better control of the power tool in unexpected situations.
• Dress properly. Do not wear loose clothing or jewelry. Keep your hair, clothing, and gloves away from moving parts. Loose clothes, jewelry, or long hair can be caught in moving parts.
• If devices are provided for the connection of dust extraction and collection facilities, ensure these are connected and properly used. The use of dust collection can reduce dust-related hazards.

Power tool use and care

• Do not force the power tool. Use the correct power tool for your application. The correct power tool will do the job better and safer at the rate at which it was designed.
• Do not use the power tool if the switch does not turn it on and off. Any power tool that cannot be controlled with the switch is dangerous and must be repaired.
• Disconnect the plug from the power source and/or the battery pack from the power tool before making any adjustments, changing accessories, or storing power tools. Such preventive safety measures reduce the risk of starting the power tool accidentally.
• Store idle power tools out of the reach of children and do not allow persons unfamiliar with the power tool or these instructions to operate the power tool. Power tools are dangerous in the hands of untrained users.
• Maintain power tools. Check for misalignment or binding of moving parts, breakage of parts, and any other condition that may affect the power tool’s operation. If damaged, have the power tool repaired before use. Many accidents are caused by poorly maintained power tools.
• Keep cutting tools sharp and clean. Properly maintained cutting tools with sharp cutting edges are less likely to bind and are easier to control.
• Use the power tool, accessories and tool bits, etc. in accordance with these instructions, taking into account the working conditions and the work to be performed. Use of the power tool for operations different from those intended could result in a hazardous situation.

Battery tool use and care 

• Recharge only with the charger specified by the manufacturer. A charger that is suitable for one type of battery pack may create a risk of fire when used with another battery pack.
•  Use power tools only with specifically designated battery packs. The use of any other battery packs may create a risk of injury and fire.
• When the battery pack is not in use, keep it away from other metal objects, like paper clips, coins, keys, nails, screws, or other small metal objects, that can make a connection from one terminal to another. Shorting the battery terminals together may cause burns or a fire.
• Under abusive conditions, liquid may be ejected from the battery; avoid contact. If contact accidentally occurs, flush with water. If liquid contacts the eyes, additionally seek medical help. Liquid ejected from the battery may cause irritation or burns.

Service 

• Have your power tool serviced by a qualified repair person using only identical replacement parts. This will ensure that the safety of the power tool is maintained.

Safety Warnings for Sander

Safety Warnings common for Grinding and Abrasive Cutting Off Operations

• This power tool is intended to function as a grinder and cutting-off machine. Read all safety warnings, instructions, illustrations, and specifications provided with this power tool. Failure to follow all instructions listed below may result in electric shock, fire, and/or serious injury.
• Operations such as sanding, wire brushing, or polishing are not recommended to be performed with this power tool. Operations for which the power tool was not designed may create a hazard and cause personal injury.
• Do not use accessories that are not specifically designed and recommended by the tool manufacturer. Just because the accessory can be attached to your power tool, it does not assure safe operation.
• The rated speed of the accessory must be at least equal to the maximum speed marked on the power tool. Accessories running faster than their rated speed can break and fly apart.
• The outside diameter and the thickness of your accessory must be within the capacity rating of your power tool. Incorrectly sized accessories cannot be adequately guarded or controlled.
• Threaded mounting of accessories must match the grinder spindle thread. For accessories mounted by flanges, the arbor hole of the accessory must fit the locating diameter of the flange. Accessories that do not match the mounting hardware of the power tool will run out of balance, vibrate excessively, and may cause loss of control.
• Do not use a damaged accessory. Before each use inspects the accessory such as abrasive wheels for chips and cracks, a backing pad for cracks, tear, or excess wear, and a wire brush for loose or cracked wires. If a power tool or accessory is dropped, inspect for damage or install an undamaged accessory. After inspecting and installing an accessory, position yourself and the bystanders away from the plane of the rotating accessory and run the power tool at maximum no-load speed for one minute. Damaged accessories will normally break apart during this test time.
• Wear personal protective equipment. Depending on the application, use a face shield, safety goggles, or safety glasses. As appropriate, wear a dust mask, hearing protectors, gloves, and a workshop apron capable of stopping small abrasive or workpiece fragments. The eye protection must be capable of stopping flying debris generated by various operations. The dust mask or respirator must be capable of filtrating particles generated by your operation. Prolonged exposure to high-intensity noise may cause hearing loss.
• Keep bystanders a safe distance away from the work area. Anyone entering the work area must wear personal protective equipment. Fragments of a workpiece or of a broken accessory may fly away and cause injury beyond the immediate area of operation.
• Hold power tool by insulated gripping surfaces only, when performing an operation where the cutting accessory may contact hidden wiring. Cutting accessory contacting a “live” wire may make exposed metal parts of the power tool “live” and shock the operator.
• Never lay the power tool down until the accessory has come to a complete stop. The spinning wheel may grab the surface and pull the power tool out of your control.
• Do not run the power tool while carrying it at your side. Accidental contact with the spinning accessory could snag your clothing, pulling the accessory into your body.
• Regularly clean the power tool’s air vents. The motor’s fan will draw the dust inside the housing and excessive accumulation of powdered metal may cause electrical hazards.
• Do not operate the power tool near flammable materials. Sparks could ignite these materials.
• Do not use accessories that require liquid coolants. Using water or other liquid coolants may result in electrocution or shock.

Kickback and Related Warnings 

• Kickback is a sudden reaction to a pinched or snagged rotating wheel, backing pad, brush, or any other accessory. Pinching or snagging causes rapid stalling of the rotating accessory which in turn causes the uncontrolled power tool to be forced in the direction opposite of the accessory’s rotation at the point of the binding. For example, if an abrasive wheel is snagged or pinched by the workpiece, the edge of the wheel that is entering into the pinch point can dig into the surface of the material causing the wheel to climb out or kick out. The wheel may either jump toward or away from the operator, depending on the direction of the wheel’s movement at the point of pinching. Abrasive wheels may also break under these conditions.
  Kickback is the result of power tool misuse and/or incorrect operating procedures or conditions and can be avoided by taking proper precautions as given below.
• Maintain a firm grip on the power tool and position your body and arm to allow you to resist kickback forces. Always use an auxiliary handle, if provided, for maximum control over kickback or torque reaction during start-up. The operator can control torque reactions or kickback forces if proper precautions are taken.
• Never place your hand near the rotating accessory. The accessory may kick back over your hand.
• Do not position your body in the area where the power tool will move if kickback occurs. Kickback will propel the tool in a direction opposite to the wheel’s movement at the point of snagging.
• Use special care when working corners, sharp edges, etc. Avoid bouncing and snagging the accessory. Corners, sharp edges, or bouncing have a tendency to snag the rotating accessory and cause loss of control or kickback.
• Do not attach a saw chain woodcarving blade or toothed saw blade. Such blades create frequent kickback and loss of control.

Safety warnings specific for Grinding and Abrasive Cutting-Off operations

• Use only wheel types that are recommended for your power tool and the specific guard designed for the selected wheel. Wheels for which the power tool was not designed cannot be adequately guarded and are unsafe.
• The grinding surface of the center depressed wheels must be mounted below the plane of the guard lip. An improperly mounted wheel that projects through the plane of the guard lip cannot be adequately protected.
• The guard must be securely attached to the power tool and positioned for maximum safety, so the least amount of wheel is exposed to the operator. The guard helps to protect the operator from broken wheel fragments, accidental contact with the wheel, and sparks that could ignite clothing.
• Wheels must be used only for recommended applications. For example: do not grind with the side of the cut-off wheel. Abrasive cut-off wheels are intended for peripheral grinding; side forces applied to these wheels may cause them to shatter.
• Always use undamaged wheel flanges that are of the correct size and shape for your selected wheel. Proper wheel flanges support the wheel thus reducing the possibility of wheel breakage. Flanges for cut-off wheels may be different from grinding wheel flanges.
• Do not use worn-down reinforced wheels from larger power tools. Wheels intended for larger power tools are not suitable for the higher speed of a smaller tool and may burst.

Additional safety warnings specific for abrasive cutting-off operations 

• Do not “jam” the cut-off wheel or apply excessive pressure. Do not attempt to make an excessive depth of cut. Overstressing the wheel increases the loading and susceptibility to twisting or binding of the wheel in the cut and the possibility of kickback or wheel breakage.
•  Do not position your body in line with and behind the rotating wheel. When the wheel, at the point of operation, is moving away from your body, the possible kickback may propel the spinning wheel and the power tool directly at you.
• When the wheel is binding or when interrupting a cut for any reason, switch off the power tool and hold the power tool motionless until the wheel comes to a complete stop. Never attempt to remove the cut-off wheel from the cut while the wheel is in motion otherwise kickback may occur. Investigate and take corrective action to eliminate the cause of wheel binding.
• Do not restart the cutting operation in the workpiece. Let the wheel reach full speed and carefully re-enter the cut. The wheel may bind, walk up or kick back if the power tool is restarted in the workpiece.
• Support panels or any oversized workpiece to minimize the risk of wheel pinching and kickback. Large workpieces tend to sag under their own weight. Supports must be placed under the workpiece near the line of cut and near the edge of the workpiece on both sides of the wheel.
• Use extra caution when making “plunge cuts” into existing walls or other blind areas. The protruding wheel may cut gas or water pipes, electrical wiring, or objects that can cause kickback.
  Additional safety warnings  Wear safety goggles.
  
• Use appropriate detectors to determine if utility lines are hidden in the work area or call the local utility company for assistance. Contact with electric lines can lead to fire and electric shock. Damaging a gas line can lead to an explosion. Penetrating a water line causes property damage.
• Release the On/Off switch and set it to the off position when the power supply is interrupted, e.g. when the battery pack is removed.
• Do not touch grinding and cutting discs before they have cooled down. The discs can become very hot while working.
• Secure the workpiece. A workpiece clamped with clamping devices or in a vice is held more secure than by hand.
• Do not open the battery. The danger of short-circuiting.
  Protect the battery against heat, e. g., against continuous intense sunlight, fire, water, and moisture. The danger of explosion.
• In case of damage and improper use of the battery, vapors may be emitted. Ventilate the area and seek medical help in case of complaints. The vapors can irritate the respiratory system.
• Use the battery only in conjunction with your Bosch product. This measure alone protects the battery against dangerous overload.
• The battery can be damaged by pointed objects such as nails or screwdrivers or by force applied externally. An internal short circuit can occur and the battery can burn,
  smoke, explode, or overheat.

Product Description and Specifications

Read all safety warnings and all instructions. Failure to follow the warnings and instructions may result in electric shock, fire and/or serious injury.

While reading the operating instructions, unfold the graphics page for the machine and leave it open.
Intended Use
The machine is intended for cutting and roughing of metal, stone and wood materials, plastics, non-ferrous metals and tiles without the use of water. A specific protection guard must be used when cutting.
Product Features
The numbering of the product features refers to the illustration of the machine on the graphics page.

Accessories shown or described are not part of the standard delivery scope of the product. A complete overview of accessories can be found in our accessories program.

Technical Data

Noise/Vibration Information

Sound emission values were determined according to EN 60745-2-3.
Typically the A-weighted noise levels of the product are: Sound pressure level 75 dB(A); Sound power level 86 dB(A).
Uncertainty K =3 dB.
Wear hearing protection!
Vibration total values ah (triax vector sum) and uncertainty K determined according to EN 60745-2-3: Surface grinding (roughing): ah =13.5 m/s 2 2 , K=1.5 m/s .
The vibration level given in this information sheet has been measured in accordance with a standardized test given in EN 60745 and may be used to compare one tool with another. It may be used for a preliminary assessment of exposure. The declared vibration emission level represents the main applications of the tool. However, if the tool is used for different applications, with different accessories or insertion tools, or is poorly maintained, the vibration emission may differ. This may significantly increase the exposure level over the total working period.
An estimation of the level of exposure to vibration should also take into account the times when the tool is switched off or when it is running but not actually doing the job. This may significantly reduce the exposure level over the total working period. Identify additional safety measures to protect the operator from the effects of vibration such as: maintaining the tool and the accessories, keeping the hands warm, and organization of work patterns.

Assembly

Battery Charging
Note: The battery supplied is partially charged. To ensure the full capacity of the battery, completely charge the battery in the battery charger before using your power tool for the first time. The lithium-ion battery can be charged at any time without reducing its service life. Interrupting the charging procedure does not damage the battery.
The lithium-ion battery is protected against deep discharging by the “Electronic Cell Protection (ECP)”. When the battery is empty, the machine is switched off by means of a protective circuit: The inserted tool no longer rotates.

• Do not continue to press the On/Off switch after the machine has been automatically switched off. The battery can be damaged.

Observe the notes for disposal.
Removing the battery (see figure A)
To remove the battery 4 press the unlocking buttons 5 and pull out the battery downwards. Do not exert any force.
Battery Charge-control Indication

Mounting the Protective Devices

•  Before any work on the machine itself (e. g. maintenance, tool change, etc.) as well as during transport and storage, remove the battery from the power tool. There is a danger of injury when unintentionally actuating the On/Off switch.

Note: After breakage of the grinding disc during operation or damage to the holding fixtures on the protection guard/power tool, the machine must promptly be sent to an after-sales service agent for maintenance. For addresses, see section “After-sales Service and Application Service”.
Protection Guard for Cutting 

• For cutting with bonded abrasives, always use the protection guard for cutting 10.
• Provide for sufficient dust extraction when cutting stone.

Mounting the blade guard (see figure B)
The protection guard for cutting 10 is mounted onto the protection guard for grinding 7 until it engages.
Adjusting the Protection Guard
Turn the protection guard to the desired position until it engages. No tool is required for this.
Mounting the Grinding Tools (see figure B)

• Before any work on the machine itself (e. g. maintenance, tool change, etc.) as well as during transport and storage, remove the battery from the power tool. There is a danger of injury when unintentionally actuating the On/Off switch.
• Do not touch grinding and cutting discs before they have cooled down. The discs can become very hot while working. Clean the grinder spindle 8 and all parts to be mounted. For tightening or loosening the grinding tools, push the spindle lock button 2 forwards and simultaneously turn the grinding tool to fix the grinder spindle.
• Actuate the spindle lock button only when the grinder spindle is at a standstill. Otherwise, the machine may become damaged.

Grinding/Cutting Disc
Pay attention to the dimensions of the grinding tools. The mounting hole diameter must fit the mounting flange without play. Do not use reducers or adapters.
When using diamond cutting discs, pay attention that the direction-of-rotation arrow on the diamond cutting disc and the direction of rotation of the machine (see direction-of-rotation arrow on the housing) agree.
See the graphics page for the mounting sequence. Attach the grinding tool using the bolt 11. Tighten the bolt using the hex key 13 until the washer of the bolt is flush with the grinding tool

•  After mounting the grinding tool and before switching it on, check that the grinding tool is correctly mounted and that it can turn freely. Make sure that the grinding tool does not graze against the protection guard or other parts.

Approved Grinding Tools
All grinding tools mentioned in these operating instructions can be used.
The permissible speed [min -1 ] or the circumferential speed [m/s] of the grinding tools used must at least match the values given in the table.
Therefore, observe the permissible rotational/circumferential speed on the label of the grinding tool.

Selecting Grinding Discs

Dust/Chip Extraction

• Dust from materials such as lead-containing coatings, some wood types, minerals, and metal can be harmful to one’s health. Touching or breathing in the dust can cause allergic reactions and/or lead to respiratory infections in the user or bystanders.
  Certain dust, such as oak or beech dust, is considered carcinogenic, especially in connection with wood-treatment additives (chromate, wood preservative). Materials containing asbestos may only be worked by specialists.
  – Provide for good ventilation of the working place.
  – It is recommended to wear a P2 filter-class respirator.
  Observe the relevant regulations in your country for the materials to be worked on.
• Prevent dust accumulation at the workplace. Dust can easily ignite.

Operation

Starting Operation
Inserting the battery
Note: Use of batteries not suitable for the machine can lead to malfunctions of or cause damage to the power tool.
Insert the charged battery 4 into the handle until it can be felt to engage and face flush against the handle.
Switching On and Off
To start the power tool, push the On/Off switch 3 forwards.
To lock the On/Off switch 3, press the On/Off switch 3 down at the front until it latches.
To switch off the power tool, release the On/Off switch 3 or, if it is locked, briefly push down the back of the On/Off switch 3 and then release it.
To save energy, only switch the power tool on when using it.

•  Check grinding tools before using. The grinding tool must be mounted properly and be able to move freely.
• Carry out a test run for at least one minute with no load.
• Do not use damaged, out-of-center, or vibrating grinding tools.
• Damaged grinding tools can burst and cause injuries.

Temperature Control/Overload Protection Indicator
The red LED indicator 6 will help you in protecting the battery against overheating and the motor against overloading.
When the LED indicator 6 continuously lights up red, the temperature of the battery is too high and the machine switches off automatically.
– Switch the power tool off.
– Allow the battery to cool down before continuing to work.
The LED indicator 6 flashes red, and the power tool is blocked and switches off automatically.
– Remove the power tool from the workpiece.
The power tool will continue to work as soon as the blockage is rectified.

Working Advice

• Exercise caution when cutting slots in structural walls; see Section “Information on Structures”.
•  When cutting lightweight materials, take into account the statutory provisions and recommendations of the material manufacturer.
•  Clamp the workpiece if it does not remain stationary due to its own weight.
•  Do not strain the machine so heavily that it comes to a standstill. 
•  After heavily straining the power tool, continue to run it at no-load for several minutes to cool down the accessory.
• Do not touch grinding and cutting discs before they have cooled down. The discs can become very hot while working.
• Do not use the power tool with a cut-off stand. When the power tool is electrostatically charged, the built-in electronic control switches it off. To restart the power tool, press the On/Off switch 3 again.

Rough Grinding 

• Never use a cutting disc for roughing.
  The best roughing results are achieved when setting the machine at an angle of 30° to 40°. Move the machine back and forth with moderate pressure. In this manner, the workpiece will not become too hot, does not discolor and no grooves are formed.

Cutting Metal

• For cutting with bonded abrasives, always use the protection guard for cutting 10. When cutting, work with moderate feed, adapted to the material being cut. Do not exert pressure on the cutting disc, tilt or oscillate the machine.
  Do not reduce the speed of running down cutting discs by applying sideward pressure.
  The machine must always work in an up-grinding motion. Otherwise, the danger exists of it being pushed uncontrolled out of the cut. When cutting profiles and square bars, it is best to start at the smallest cross-section.

Cutting Stone

• Provide for sufficient dust extraction when cutting stone.
• Wear a dust respirator.
• The machine may be used only for dry cutting/grinding. For cutting stone, it is best to use a diamond cutting disc. For cutting especially hard material, e. g., concrete with high pebble content, the diamond cutting disc can overheat and become damaged as a result. This is clearly indicated by circular sparking, rotating with the diamond cutting disc. In this case, interrupt the cutting process and allow the diamond cutting disc to cool by running the machine for a short time at maximum speed with no load. Noticeably decreasing work progress and circular sparking are indications of a diamond cutting disc that has become dull. Briefly cutting into abrasive material (e. g. lime-sand brick) can resharpen the disc again.

Information on Structures

Slots in structural walls are subject to the Standard DIN 1053 Part 1, or country-specific regulations. These regulations are to be observed under all circumstances. Before beginning work, consult the responsible structural engineer, architect, or construction supervisor.
Recommendations for Optimal Handling of the Battery
Store the battery only within a temperature range between
–20 °C and 50 °C. As an example, do not leave the battery in the car in summer.
A significantly reduced working period after charging indicates that the battery is used and must be replaced.
Observe the notes for disposal.

Maintenance and Service

Maintenance and Cleaning

•  Before any work on the machine itself (e. g. maintenance, tool change, etc.) as well as during transport and storage, remove the battery from the power tool. There is a danger of injury when unintentionally actuating the On/Off switch.
• For safe and proper working, always keep the machine and ventilation slots clean.
  Please store and handle the accessory(-ies) carefully.

After-sales Service and Application Service
Our after-sales service responds to your questions concerning maintenance and repair of your product as well as spare parts. Exploded views and information on spare parts can also be found under: www.bosch-pt.com
Bosch’s application service team will gladly answer questions concerning our products and their accessories.
In all correspondence and spare parts orders, please always include the 10-digit article number given on the nameplate of the product.

Transport The contained lithium-ion batteries are subject to the Dangerous Goods Legislation requirements. The user can transport the batteries by road without further requirements.
When being transported by third parties (e.g.: air transport or forwarding agency), special requirements on packaging and labeling must be observed. For the preparation of the item being shipped, consulting an expert for hazardous material is required.
Dispatch batteries only when the housing is undamaged. Tape or mask off open contacts and pack up the battery in such a manner that it cannot move around in the packaging. Please also observe possibly more detailed national regulations.

EU Declaration of Conformity
Grinder
Article number
We declare under our sole responsibility that the stated products comply with all applicable provisions of the directives and regulations listed below and are in conformity with the following standards.
Technical file at: *

* Robert Bosch Power Tools GmbH (PT/ECS) 70538 Stuttgart
GERMANY

Robert Bosch Power Tools GmbH, 70538 Stuttgart, GERMANY Stuttgart, 01.01.2017

Robert Bosch Power Tools GmbH
70538 Stuttgart
GERMANY
www.bosch-pt.com
1 609 92A 29F (2016.07) O / 257