Bosch GEX Professional Random Orbital Sander

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" refers to mains-operated or battery-operated power tools.

Work Area Safety

• Keep work area clean and well lit. Cluttered or dark areas invite accidents.
• Do not operate power tools in explosive atmospheres (flammable liquids, gases, dust). Power tools create sparks that may ignite dust or fumes.
• Keep children and bystanders away. Distractions can cause loss of control.

Electrical Safety

• Power tool plugs must match the outlet. Never modify the plug. Do not use adapter plugs with earthed tools.
• Avoid body contact with earthed surfaces (pipes, radiators, ranges, refrigerators).
• Do not expose power tools to rain or wet conditions.
• Do not abuse the cord. Keep cord away from heat, oil, sharp edges, and moving parts.
• When operating outdoors, use an extension cord suitable for outdoor use.
• If operating in damp locations is unavoidable, use a residual current device (RCD) protected supply.

Personal Safety

• Stay alert, watch what you are doing, and use common sense. Do not use while tired or under the influence of drugs, alcohol, or medication.
• Use personal protective equipment. Always wear eye protection. Use dust masks, non-skid shoes, hard hats, or hearing protection as appropriate.
• Prevent unintentional starting. Ensure the switch is in the off-position before connecting to power or battery.
• Remove any adjusting key or wrench before turning the power tool on.
• Do not overreach. Keep proper footing and balance.
• Dress properly. Do not wear loose clothing or jewellery. Keep hair, clothing, and gloves away from moving parts.
• If dust extraction facilities are provided, ensure they are connected and properly used.

Power Tool Use and Care

• Do not force the power tool. Use the correct tool for your application.
• Do not use if the switch does not turn it on and off.
• Disconnect the plug from the power source and/or battery pack before making adjustments, changing accessories, or storing.
• Store idle power tools out of reach of children and unfamiliar persons.
• Maintain power tools. Check for misalignment, binding, or breakage. Have damaged tools repaired.
• Keep cutting tools sharp and clean.
• Use the power tool, accessories, and bits in accordance with instructions, considering working conditions.

Service

• Have your power tool serviced by a qualified repair person using only identical replacement parts.

Safety Warnings for Sander

• Use the machine only for dry sanding. Water penetration increases electric shock risk.
• Beware of sparking. Remove combustible materials nearby.
• ⚠️ Caution, fire hazard! Avoid overheating the object and the sander. Always empty the dust collector before breaks. Sanding debris can self-ignite, especially when mixed with chemicals or hot.
• Hold the machine firmly with both hands and provide a secure stance.
• Secure the workpiece with clamping devices or a vice.
• (GB specific) Product fitted with BS 1363/A approved plug.
• (AUS/NZ specific) Use an RCD with rated residual current of 30 mA or less.

Product Description and Specifications

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

Intended Use

The machine is intended for dry sanding of wood, plastic, metal, filler, and coated surfaces. Models with electronic control are also suitable for polishing.

Product Features

The numbering of features refers to the illustration:

• [Part 1] Auxiliary handle (insulated gripping surface)*
• [Part 2] Screw for auxiliary handle*
• [Part 3] Thumbwheel for orbit frequency preselection (GEX 125 AC/GEX 150 AC)
• [Part 4] On/Off switch
• [Part 5] Lock-on button for On/Off switch
• [Part 6] Dust box, complete (Microfilter System)*
• [Part 7] Allen key
• [Part 8] Sanding plate
• [Part 9] Handle (insulated gripping surface)
• [Part 10] Sanding sheet*
• [Part 11] Screw for fastening the sanding plate
• [Part 12] Holder for dust box*
• [Part 13] Plastic slider
• [Part 14] Extraction outlet
• [Part 15] Latching lever for dust box*
• [Part 16] Filter element (Microfilter System)*
• [Part 17] Extraction adapter*
• [Part 18] Vacuum hose*
• [Part 19] Dust bag*

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

Technical Data

Random Orbital Sander GEX ... Professional

The values given are valid for a nominal voltage [U] of 230 V. For different voltages and models for specific countries, these values can vary. Please observe the article number on the type plate of your machine. The trade names of the individual machines may vary.

Noise/Vibration Information

Measured sound values determined according to EN 60745.

• A-weighted sound pressure level: Typically 75 dB(A). Uncertainty K = 3 dB.
• Noise level during work can exceed 80 dB(A). Wear hearing protection!
• Vibration total values (triax vector sum) according to EN 60745: Vibration emission value a<0xE2><0x82><0x95> = 4.0 m/s², Uncertainty K = 1.5 m/s².

The vibration emission level is measured according to a standardised test (EN 60745) and can be used for comparison. It may differ based on applications, accessories, or maintenance. Consider times when the tool is switched off or not in use for exposure estimation. Identify additional safety measures to protect the operator from vibration effects.

Declaration of Conformity

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

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

Signed by: Dr. Egbert Schneider (Senior Vice President Engineering) and Dr. Eckerhard Strötgen (Head of Product Certification).

Date: Leinfelden, 15.12.2010

Assembly

Before any work on the machine, pull the mains plug. ?

Replacing the Sanding Sheet (see figure A)

Referencing Figure A:

• Remove dust or debris from the sanding plate [Part 8] with a brush.
• The sanding plate [Part 8] has a Velcro backing for quick attachment of sanding sheets [Part 10].
• Press the sanding sheet [Part 10] firmly against the bottom side of the sanding plate [Part 8].
• Ensure punched holes in the sanding sheet match the holes in the sanding plate for optimum dust extraction.

Selecting the Sanding Sheet

Choose sanding sheets based on material and required removal rate.

Selection of the Sanding Plate

• Soft sanding plate: Suitable for polishing and sensitive sanding (curved surfaces).
• Medium sanding plate: Suitable for all sanding applications and general use.
• Hard sanding plate: Suitable for high sanding capacity on flat surfaces.

Replacing the Sanding Plate (see figure B)

Referencing Figure B:

• Note: Replace a damaged sanding plate [Part 8] immediately.
• Pull off the sanding sheet or polishing tool.
• Unscrew screw [Part 11] and remove sanding plate [Part 8].
• Attach the new sanding plate [Part 8] and tighten the screw [Part 11].
• Note: Ensure the toothing of the drive element engages into the openings of the sanding plate.

Dust/Chip Extraction

⚠️ Dusts from materials like lead-containing coatings, some wood types, minerals, and metal can be harmful. Allergic reactions or respiratory infections may occur. Certain dusts (e.g., oak, beech) are carcinogenic, especially with additives. Asbestos-containing materials require specialists.

• Use a dust extraction system suitable for the material.
• Provide good ventilation.
• It is recommended to wear a P2 filter-class respirator.
• Observe relevant country regulations for materials being worked.
• Prevent dust accumulation at the workplace, as dusts can easily ignite.

Operation

Starting Operation

• Observe correct mains voltage! Voltage must match the nameplate. (230 V tools can operate on 220 V).

Switching On and Off

• To start: Press and hold the On/Off switch [Part 4].
• To lock: Press the lock-on button [Part 5] while the switch [Part 4] is pressed.
• To switch off: Release the On/Off switch [Part 4], or briefly press and release it if locked.

Integrated Dust Extraction with Dust Box (see figures C1-C4)

Referencing Figures C1-C4:

• Before assembling dust box [Part 6], pull out plastic slider [Part 13].
• Place dust box [Part 6] onto extraction outlet [Part 14] and engage. Ensure plastic slider [Part 13] engages in holder [Part 12].
• To empty dust box [Part 6]: Press latching levers [Part 15] and pull box downwards.
• Before opening, loosen dust from filter element [Part 16] by striking against a firm support.
• Grasp dust box [Part 6] by recessed grip, fold filter element [Part 16] upward, and empty box. Clean filter element plates with a soft brush.

External Dust Extraction (see figure D)

Referencing Figure D:

• Slide extraction adapter [Part 17] onto outlet piece [Part 14]. Ensure latching levers engage.
• The adapter [Part 17] accepts a vacuum hose with a 19 mm diameter.
• To remove adapter [Part 17]: Press latching levers at the rear and pull adapter off.
• The vacuum cleaner must be suitable for the material being worked. Use a special vacuum cleaner for dry dust that is detrimental to health or carcinogenic.

Internal Dust Extraction with Dust Bag (see figure E)

Referencing Figure E:

• For small sanding jobs, a dust bag (accessory) [Part 19] can be connected.
• Before mounting dust bag [Part 19], pull out plastic slider [Part 13].
• Slide dust-bag sleeve firmly over extraction outlet [Part 14]. Ensure plastic slider [Part 13] engages in the holder on the dust bag [Part 19].
• To maintain optimum dust collection, empty the dust bag [Part 19] in good time.

Auxiliary Handle

The auxiliary handle [Part 1] enables convenient handling and optimal distribution of power, especially at high removal rates. Fasten the auxiliary handle [Part 1] with screw [Part 2] to the casing.

Preselecting the Orbital Stroke Rate (GEX 125 AC/GEX 150 AC)

Use the thumbwheel [Part 3] to preselect the required orbital stroke rate, even during operation.

• 1-2: Low stroke rate
• 3-4: Medium stroke rate
• 5-6: High stroke rate

The required stroke rate depends on the material and working conditions. Constant electronic control maintains stroke rate under load for uniform performance. After long periods of low stroke rate work, run the machine at maximum stroke rate for approx. 3 minutes with no load to cool down.

Sanding Plate Brake

An integrated sanding plate brake reduces stroke rate at no-load to prevent scoring when placing the machine on the workpiece. If the no-load stroke rate continuously increases, the sanding plate is damaged and must be replaced, or the brake is worn. A worn brake must be replaced by an authorized after-sales service agent.

Working Advice

• Before any work on the machine, pull the mains plug. ?
• Wait until the machine has come to a standstill before placing it down.

Sanding Surfaces

Switch the machine on, place it with the complete sanding surface on the area to be worked, and move with moderate pressure. Removal capacity and pattern are determined by sanding sheet, preselected stroke rate, and applied pressure. Use only flawless sanding sheets. Apply uniform sanding pressure; increasing pressure does not increase capacity but increases wear. Sanding sheets used for metal should not be used for other materials. Use only original Bosch sanding accessories.

Rough Sanding

Attach a sanding sheet with coarse grain. Apply light pressure to achieve higher stroke rate and high material removal.

Fine Sanding

Attach a sanding sheet with fine grain. Lightly vary application pressure or stroke rate to reduce sanding plate stroke rate while maintaining orbital action. Move the machine in a circular or lengthwise/crosswise pattern with moderate pressure. Do not tilt the machine to avoid sanding through the workpiece (e.g., veneer). Switch off after use.

Polishing (GEX 125 AC/GEX 150 AC)

For polishing weathered paint or buffing scratches (e.g., acrylic glass), use appropriate accessories (lamb's wool bonnet, polishing felt, sponge). Select a low stroke rate (setting 1-2) for polishing to avoid excessive heating. Apply polish to a smaller surface than intended. Work polish in crosswise or circular motion with moderate pressure. Do not let polish dry on the surface. Clean polishing accessories regularly.

Maintenance and Service

Maintenance and Cleaning

• Before any work, pull the mains plug. ?
• Keep the machine and ventilation slots clean for safe and proper working.

If the machine fails, repair should be carried out by an after-sales service centre for Bosch power tools. Always include the 10-digit article number from the type plate in all correspondence and spare parts orders.

After-sales Service and Customer Assistance

For maintenance, repair, and spare parts information, visit www.bosch-pt.com. Customer service representatives can answer questions concerning applications and adjustments.

Contact Information

Great Britain
Robert Bosch Ltd. (B.S.C.)
P.O. Box 98, Broadwater Park, North Orbital Road, Denham, Uxbridge UB 9 5HJ
Tel. Service: +44 (0844) 736 0109
Fax: +44 (0844) 736 0146
E-Mail: boschservicecentre@bosch.com

Ireland
Origo Ltd.
Unit 23 Magna Drive, Magna Business Park, City West, Dublin 24
Tel. Service: +353 (01) 4 66 67 00
Fax: +353 (01) 4 66 68 88

Australia, New Zealand and Pacific Islands
Robert Bosch Australia Pty. Ltd.
Power Tools, Locked Bag 66, Clayton South VIC 3169
Customer Contact Center:
Inside Australia: Phone: +61 (01300) 307 044, Fax: +61 (01300) 307 045
Inside New Zealand: Phone: +64 (0800) 543 353, Fax: +64 (0800) 428 570
Outside AU and NZ: Phone: +61 (03) 9541 5555
Website: www.bosch.com.au

Republic of South Africa
Customer service Hotline: +27 (011) 6 51 96 00
Gauteng - BSC Service Centre: 35 Roper Street, New Centre, Johannesburg
Tel.: +27 (011) 4 93 93 75, Fax: +27 (011) 4 93 01 26
E-Mail: bsctools@icon.co.za
KZN - BSC Service Centre: Unit E, Almar Centre, 143 Crompton Street, Pinetown
Tel.: +27 (031) 7 01 21 20, Fax: +27 (031) 7 01 24 46
E-Mail: bsc.dur@za.bosch.com
Western Cape - BSC Service Centre: Democracy Way, Prosperity Park, Milnerton
Tel.: +27 (021) 5 51 25 77, Fax: +27 (021) 5 51 32 23
E-Mail: bsc@zsd.co.za

Bosch Headquarters
Midrand, Gauteng
Tel.: +27 (011) 6 51 96 00
Fax: +27 (011) 6 51 98 80
E-Mail: rbsa-hq.pts@za.bosch.com

People's Republic of China
China Mainland
Bosch Power Tools (China) Co., Ltd.
567, Bin Kang Road, Bin Jiang District 310052, Hangzhou, P.R. China
Service Hotline: 400 826 8484
Fax: +86 571 8777 4502
E-Mail: contact.ptcn@cn.bosch.com
Website: www.bosch-pt.com.cn

HK and Macau Special Administrative Regions
Robert Bosch Hong Kong Co. Ltd.
21st Floor, 625 King's Road, North Point, Hong Kong
Customer Service Hotline: +852 (21) 02 02 35
Fax: +852 (25) 90 97 62
E-Mail: info@hk.bosch.com
Website: www.bosch-pt.com.hk

Indonesia
PT. Multi Tehaka
Kawasan Industri Pulogadung, Jalan Rawa Gelam III No. 2, Jakarta 13930, Indonesia
Tel.: +62 (21) 46 83 25 22
Fax: +62 (21) 46 82 86 45/68 23
E-Mail: sales@multitehaka.co.id
Website: www.multitehaka.co.id

Philippines
Robert Bosch, Inc.
28th Floor Fort Legend Towers, 3rd Avenue corner 31st Street, Fort Bonifacio Global City, 1634 Taguig City, Philippines
Tel.: +63 (2) 870 3871
Fax: +63 (2) 870 3870
E-Mail: matheus.contiero@ph.bosch.com
Website: www.bosch-pt.com.ph
Bosch Service Center:
9725-27 Kamagong Street, San Antonio Village, Makati City, Philippines
Tel.: +63 (2) 899 9091
Fax: +63 (2) 897 6432
E-Mail: rosalie.dagdagan@ph.bosch.com

Malaysia
Robert Bosch (S.E.A.) Pte. Ltd.
No. 8A, Jalan 13/6, G.P.O. Box 10818, 46200 Petaling Jaya, Selangor, Malaysia
Tel.: +60 (3) 7966 3194
Fax: +60 (3) 7958 3838
E-Mail: cheehoe.on@my.bosch.com
Toll-Free: 1800 880 188
Website: www.bosch-pt.com.my

Thailand
Robert Bosch Ltd.
Liberty Square Building, No. 287, 11 Floor, Silom Road, Bangrak, Bangkok 10500
Tel.: +66 (2) 6 31 1879–1888 (10 lines)
Fax: +66 (2) 2 38 47 83
Robert Bosch Ltd., P. O. Box 2054, Bangkok 10501, Thailand
Bosch Service - Training Centre
2869-2869/1 Soi Ban Kluay, Rama IV Road (near old Paknam Railway), Prakanong District, 10110 Bangkok, Thailand
Tel.: +66 (2) 671 7800–4
Fax: +66 (2) 2 49 42 96
Fax: +66 (2) 2 49 52 99

Singapore
Robert Bosch (SEA) Pte. Ltd.
11 Bishan Street 21, Singapore 573943
Tel.: +65 6571 2772
Fax: +65 6350 5315
E-Mail: leongheng.leow@sg.bosch.com
Toll-Free: 1800 333 8333
Website: www.bosch-pt.com.sg

Vietnam
Robert Bosch Vietnam Co. Ltd
10/F, 194 Golden Building, 473 Dien Bien Phu Street, Ward 25, Binh Thanh District, 84 Ho Chi Minh City, Vietnam
Tel.: +84 (8) 6258 3690 ext. 413
Fax: +84 (8) 6258 3692
E-Mail: hieu.lagia@vn.bosch.com
Website: www.bosch-pt.com

Disposal

The machine, accessories, and packaging should be sorted for environmental-friendly recycling. Do not dispose of power tools into household waste!

Only for EC countries: According to the European Guideline 2002/96/EC for Waste Electrical and Electronic Equipment and its implementation into national right, power tools that are no longer usable must be collected separately and disposed of in an environmentally correct manner.