Bosch GWS Professional Angle Grinder

Safety Notes

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

1) Work Area Safety

• Keep work area clean and well lit.
• Do not operate in explosive atmospheres.
• Keep children and bystanders away.

2) Electrical Safety

• Ensure power tool plugs match the outlet.
• Avoid body contact with earthed or grounded surfaces.
• Do not expose power tools to rain or wet conditions.
• Do not abuse the cord.
• Use outdoor-suitable extension cords when operating outdoors.
• Use an RCD-protected supply in damp locations.

3) Personal Safety

• Stay alert and use common sense. Do not operate when tired or under the influence of drugs/alcohol.
• Use personal protective equipment (eye protection, dust mask, safety shoes, hearing protection).
• Prevent unintentional starting by ensuring the switch is off before connecting to power.
• Remove adjusting keys or wrenches before operation.
• Maintain proper footing and balance; do not overreach.
• Do not wear loose clothing or jewelry; keep hair and clothing away from moving parts.

4) Power Tool Use and Care

• Do not force the power tool; use the correct tool for the application.
• Do not use if the switch does not operate correctly.
• Disconnect from power source before making adjustments or changing accessories.
• Store idle tools out of reach of children and untrained users.
• Maintain power tools; check for misalignment or binding. Have damaged tools repaired.
• Keep cutting tools sharp and clean.
• Use tools and accessories according to instructions and working conditions.
• If dust extraction facilities are provided, ensure they are connected and used properly.

5) Service

• Have power tools serviced by a qualified repair person using identical replacement parts.

Safety Warnings for Angle Grinder

Common Warnings for Grinding, Sanding, Wire Brushing, or Abrasive Cutting Off Operations

• This power tool is intended for grinding, sanding, wire brushing, or cut-off operations.
• Not recommended for polishing.
• Use only accessories specifically designed and recommended by the manufacturer.
• Accessory speed must be at least equal to the tool's maximum speed.
• Accessory diameter and thickness must be within the tool's capacity rating.
• Arbor size of accessories must fit the spindle properly.
• Do not use damaged accessories. Inspect before each use.
• Wear appropriate personal protective equipment.
• Keep bystanders a safe distance away from the work area.
• Hold power tool by insulated gripping surfaces only.
• Position the cord clear of the spinning accessory.
• Never lay the power tool down until the accessory has stopped completely.
• Do not run the power tool while carrying it at your side.
• Regularly clean air vents.
• Do not operate near flammable materials.
• Do not use accessories requiring liquid coolants.

Kickback and Related Warnings

Kickback is a sudden reaction to a pinched or snagged rotating accessory, causing the tool to be forced in the opposite direction. It can result in serious injury. Take proper precautions to avoid kickback:

• Maintain a firm grip and position your body to resist kickback forces. Use auxiliary handle.
• Never place your hand near the rotating accessory.
• Do not position your body in the area where the tool will move if kickback occurs.
• Use special care with corners, sharp edges, and avoid bouncing or snagging.
• Do not attach saw chain woodcarving blades or toothed saw blades.

Additional Safety Instructions for Grinding and Cutting Off Operations

• Use only recommended wheel types and guards.
• Ensure the guard is securely attached and positioned for maximum safety.
• Use wheels only for recommended applications (e.g., do not grind with the side of a cut-off wheel).
• Always use undamaged wheel flanges of the correct size and shape.
• Do not use worn-down wheels from larger power tools.

Additional Safety Warnings Specific for Abrasive Cutting Off Operations

• Do not "jam" the cut-off wheel or apply excessive pressure.
• Do not position your body in line with and behind the rotating wheel.
• When wheel is binding, switch off the tool and hold it motionless until it stops.
• Do not restart a cut in the workpiece without the wheel reaching full speed.
• Support panels or oversized workpieces to minimize pinching and kickback.

Safety Warnings Specific for Sanding Operations

• Do not use excessively oversized sanding disc paper.

Safety Warnings Specific for Wire Brushing Operations

• Be aware that wire bristles can be thrown. Do not overstress the brush.
• If a guard is recommended, ensure it does not interfere with the wire wheel or brush.

Additional Safety Warnings

• Wear safety goggles. ?
• Use suitable detectors to determine if utility lines are hidden in the work area.
• Release the On/Off switch when power is interrupted.
• When working stone, use dust extraction.
• Always hold the machine firmly with both hands and provide for a secure stance.
• Secure the workpiece with clamping devices or a vice.
• Keep your workplace clean.
• Never use the machine with a damaged cable.

Functional Description

The machine is intended for cutting, roughing, and brushing of metal and stone materials without water. A special cutting guide is required for cutting with bonded abrasives. Dust extraction is necessary when cutting stone. The machine can be used for sanding with approved sanding tools.

Product Features

The following parts are illustrated on the graphics page:

• 1 Spindle lock button: Locks the grinder spindle.
• 2 On/Off switch: Controls power to the tool.
• 3 Allen key: Used for tightening screws.
• 4 Thumbwheel for speed preselection: Allows speed adjustment for specific models (GWS 6-100 E/GWS 6-115 E/GWS 6-125 E/GWS 850 CE).
• 5 Auxiliary handle: Provides a secure grip and control.
• 6 Grinder spindle: The shaft onto which accessories are mounted.
• 7 Protection guard for grinding: Protects the user during grinding operations.
• 8 Locking screw for protection guard: Secures the guard in place.
• 9 Mounting flange with O-ring: Mounts the grinding disc to the spindle.
• 10 Grinding disc: The primary cutting or grinding accessory.
• 11 Clamping nut: Secures the grinding disc to the spindle.
• 12 Quick-clamping nut SDS-clic: An alternative, tool-free nut for securing discs.
• 13 Carbide grinding head: An accessory for specific tasks.
• 14 Protection guard for cutting: Specifically designed for cutting operations.
• 15 Cutting disc: Used for cutting materials.
• 16 Hand guard: Provides additional hand protection for certain accessories.
• 17 Rubber sanding plate: Used with sanding sheets.
• 18 Sanding sheet: Abrasive material for sanding.
• 19 Round nut: Used with certain accessories.
• 20 Cup brush: Accessory for cleaning or deburring.
• 21 Cutting guide with dust extraction protection guard: Aids in dust management during cutting.
• 22 Diamond cutting disc: For cutting hard materials like stone or concrete.
• 23 Handle: An alternative handle for specific models.

* Accessories shown or described may not be part of the standard delivery scope.

Noise/Vibration Information

Measured sound values are typically:

• Sound pressure level: 86 dB(A)
• Sound power level: 97 dB(A)
• Uncertainty K: 3 dB

Wear hearing protection!

Vibration total values (triax vector sum) determined according to EN 60745:

• Surface grinding: Vibration emission value a_h = 7.0 m/s², Uncertainty K=1.5 m/s²
• Disk sanding: Vibration emission value a_h = 4.0 m/s², Uncertainty K=1.5 m/s²

The declared vibration emission level is measured according to a standardized test and can be used for comparison. Actual exposure may vary based on application, accessories, and maintenance. It is recommended to estimate exposure levels considering times when the tool is not in use.

Declaration of Conformity

Robert Bosch GmbH declares that the product described under "Technical Data" conforms to standards and directives including EN 60745, 2004/108/EC, and 2006/42/EC.

Technical file maintained at: Robert Bosch GmbH, PT/ESC, D-70745 Leinfelden-Echterdingen.

Signatures from Dr. Egbert Schneider (Senior Vice President Engineering) and Dr. Eckerhard Strötgen (Head of Product Certification) dated 01.03.2010.

Technical Data

Values are valid for nominal voltages of 230/240 V. Values may vary for lower voltages or specific country models. Observe the article number on the machine's type plate.

Assembly

Mounting the Protective Devices

• Before any work on the machine, pull the mains plug.
• Protection Guard for Grinding: Place guard (7) on the spindle collar, adjust position, and tighten locking screw (8) with allen key (3). Ensure guard prevents sparking towards the operator.
• Protection Guard for Cutting: Always use protection guard (14) for cutting with bonded abrasives. Mount it similarly to the grinding guard.
• Cutting Guide with Dust Extraction Protection Guard: Mount cutting guide (21) similarly to the protection guard for grinding (7).

Auxiliary Handle

• Operate the machine only with the auxiliary handle (5).
• Screw the auxiliary handle (5) onto the right or left of the machine head depending on the working method.

Hand Guard

• For operations with rubber sanding plate (17), cup brush/wheel brush/flap disc, always mount the hand guard (16).
• The hand guard (16) is fastened with the auxiliary handle (5).

Mounting the Grinding Tools

• Before any work, pull the mains plug.
• Grinding and cutting discs become hot; do not touch until cooled.
• Clean the grinder spindle (6) and parts.
• Lock the grinder spindle with the spindle lock button (1) for clamping/loosening tools. Actuate button only when spindle is standstill.
• Grinding/Cutting Disc: Ensure mounting hole diameter fits the flange without play. Do not use reducers. For diamond cutting discs, ensure rotation direction matches the machine's. Screw on clamping nut (11) and tighten with a two-pin spanner. After mounting, check that the tool turns freely and does not graze against the guard or other parts.
• Mounting flange for grinding spindle M 14: Ensure O-ring is present and undamaged; replace if necessary (article number 1 600 210 039).
• Flap Disc: Always mount the hand guard (16).
• Rubber Sanding Plate: Always mount the hand guard (16). Screw on round nut (19) and tighten with a two-pin spanner.
• Cup Brush/Disc Brush: Always mount the hand guard (16). Screw brush onto spindle until it rests firmly against the flange. Tighten with an open-end spanner.

Quick-clamping Nut SDS-clic

• Used for convenient, tool-free changing of grinding tools. May only be used for grinding or cutting discs.
• Use only flawless, undamaged quick-clamping nuts (12).
• When screwing on, ensure the printed side does not face the grinding disc; the arrow must point to the index mark (24).
• Lock spindle with button (1). Turn nut (12) clockwise to tighten.
• To loosen, turn the knurled ring counter-clockwise. Never use pliers; use the two-pin spanner.

Approved Grinding Tools

Grinding tools must have a permissible speed [min⁻¹] or circumferential speed [m/s] at least matching the tool's specifications. Observe the speed rating on the tool label.

Rotating the Machine Head

• Before any work, pull the mains plug.
• The machine head can be rotated in 90° steps for more convenient switch positioning, e.g., for left-handed users.
• Unscrew the four screws, rotate the head carefully, and retighten the screws.

Operation

Dust/Chip Extraction

• Dust from certain materials can be harmful. Use dust extraction whenever possible.
• Provide for good ventilation.
• A P2 filter-class respirator is recommended.
• Observe relevant country regulations for materials being worked.

Starting Operation

• Observe correct mains voltage; it must agree with the voltage on the machine's nameplate. Tools marked 230 V can also operate with 220 V.
• When using mobile generators, ensure they have sufficient reserve capacity and suitable voltage control to avoid performance issues.

Switching On and Off

• To start: Push On/Off switch (2) forward.
• To lock ON: Press the front of the switch (2) down until it latches.
• To switch off: Release the switch (2) or briefly push the back of the locked switch down and release.
• Before Use: Check grinding tools for proper mounting and free movement. Perform a one-minute test run with no load. Do not use damaged, out-of-centre, or vibrating tools.

Reduced Starting Current (GWS 850 C/GWS 850 CE)

Limits power consumption on startup, enabling operation from a 13 A fuse.

Constant Electronic Control (GWS 850 C/GWS 850 CE)

Maintains constant speed under load for uniform performance.

Speed Preselection

Required speed can be preselected with thumbwheel (4).

Working Advice

• Use caution when cutting slots in structural walls.
• Clamp workpieces that may not remain stationary.
• Do not strain the machine to the point of standstill.
• After heavy strain, run the tool at no-load for several minutes to cool the accessory.
• Grinding and cutting discs get very hot; allow them to cool before touching.
• Do not use the power tool with a cut-off stand.
• Rough Grinding: Never use a cutting disc for roughing. Set machine at 30°-40° angle. Move back and forth with moderate pressure.
• Flap Disc: Suitable for curved surfaces and profiles, offering longer service life and lower temperatures than sanding sheets.
• Cutting Metal: Always use the protection guard for cutting (14). Work with moderate feed, adapted to the material. Do not exert excessive pressure, tilt, or oscillate the machine. Do not reduce cutting disc speed by sideward pressure. The machine must work in an up-grinding motion to avoid uncontrolled movement out of the cut. When cutting profiles/square bar, start at the smallest cross section.
• Cutting Stone: Provide sufficient dust extraction. Wear a dust respirator. Use only dry cutting/grinding. Diamond cutting discs are recommended. Ensure vacuum cleaner is approved for masonry dust if using cutting guide with dust extraction. Slide machine with moderate feed. If diamond disc overheats (indicated by circular sparking), interrupt cutting and allow it to cool. Dull discs may be resharpened by briefly cutting into abrasive material.
• Information on Structures: Slots in structural walls are subject to regulations (e.g., DIN 1053 Part 1). Consult a structural engineer, architect, or supervisor before work.

Maintenance and Service

Maintenance and Cleaning

• Before any work, pull the mains plug.
• Keep the machine and ventilation slots clean for safe working.
• In extreme conditions, use dust extraction. Blow out ventilation slots frequently. Install an RCD.
• Store and handle accessories carefully.
• If the machine fails, have it repaired by an after-sales service centre for Bosch power tools.
• Always include the 10-digit article number when ordering spare parts or in correspondence.

After-sales Service and Customer Assistance

For questions concerning maintenance, repair, or spare parts, contact Bosch after-sales service. Exploded views and spare parts information are available at www.bosch-pt.com.

Customer service representatives can answer questions about applications and adjustments.

Disposal

Sort machine, accessories, and packaging for environmentally friendly recycling. For EC countries, do not dispose of power tools in household waste; collect separately and dispose of correctly according to European Guideline 2002/96/EC.