tions provided with this power tool. Failure to follow all in-
structions listed below 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 mainsoperated (corded) power tool or battery-operated (cordless) power tool.
Work area safety
u Keep work area clean and well lit. Cluttered or dark
areas invite accidents.
u Do not operate power tools in explosive atmospheres,
such as in the presence of flammable liquids, gases or
dust. Power tools create sparks which may ignite the dust
or fumes.
u Keep children and bystanders away while operating a
power tool. Distractions can cause you to lose control.
Electrical safety
u 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 risk of electric shock.
u Avoid body contact with earthed or grounded sur-
faces, such as pipes, radiators, ranges and refrigerators. There is an increased risk of electric shock if your
body is earthed or grounded.
u Do not expose power tools to rain or wet conditions.
Water entering a power tool will increase the risk of electric shock.
u Do not abuse the cord. Never use the cord for carry-
ing, pulling or unplugging the power tool. Keep cord
away from heat, oil, sharp edges or moving parts.
Damaged or entangled cords increase the risk of electric
shock.
u When operating a power tool outdoors, use an exten-
sion cord suitable for outdoor use. Use of a cord suitable for outdoor use reduces the risk of electric shock.
u If operating a power tool in a damp location is un-
avoidable, use a residual current device (RCD) protected supply. Use of an RCD reduces the risk of electric
shock.
Personal safety
u 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 inatten-
Read all safety warnings, instructions, illustrations and specifica-
tion while operating power tools may result in serious personal injury.
u Use personal protective equipment. Always wear eye
protection. Protective equipment such as a dust mask,
non-skid safety shoes, hard hat, or hearing protection
used for appropriate conditions will reduce personal injuries.
u Prevent unintentional starting. Ensure the switch is in
the off-position before connecting to power source
and/or battery pack, picking up or carrying the tool.
Carrying power tools with your finger on the switch or energising power tools that have the switch on invites accidents.
u 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.
u Do not overreach. Keep proper footing and balance at
all times. This enables better control of the power tool in
unexpected situations.
u Dress properly. Do not wear loose clothing or jew-
ellery. Keep your hair and clothing away from moving
parts. Loose clothes, jewellery or long hair can be caught
in moving parts.
u If devices are provided for the connection of dust ex-
traction and collection facilities, ensure these are connected and properly used. Use of dust collection can re-
duce dust-related hazards.
u Do not let familiarity gained from frequent use of tools
allow you to become complacent and ignore tool
safety principles. A careless action can cause severe in-
jury within a fraction of a second.
Power tool use and care
u 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 for which it was designed.
u 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.
u Disconnect the plug from the power source and/or re-
move the battery pack, if detachable, 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.
u 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.
u Maintain power tools and accessories. Check for mis-
alignment 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.
1 609 92A 4AJ | (24.05.2018)Bosch Power Tools
English | 7
u Keep cutting tools sharp and clean. Properly main-
tained cutting tools with sharp cutting edges are less
likely to bind and are easier to control.
u 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.
u Keep handles and grasping surfaces dry, clean and
free from oil and grease. Slippery handles and grasping
surfaces do not allow for safe handling and control of the
tool in unexpected situations.
Service
u 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
u Only use the power tool for dry sanding. Water entering
a power tool will increase the risk of electric shock.
u Ensure that no persons are at risk due to flying sparks.
Remove combustible materials from the surrounding
area. Flying sparks are created when sanding metals.
u Warning: Danger of fire! Avoid overheating the work-
piece and the sander. Always empty the dust collector
before taking a break from work. Sanding dust in the
dust bag, microfilter, paper bag (or in the filter bag or vacuum cleaner filter) can spontaneously combust under
certain conditions, for example if flying sparks are created when sanding metals. This risk is increased if the
sanding dust is mixed with paint or polyurethane residue
or with other chemical substances and if the workpiece is
hot as a result of prolonged work.
u Clean the air vents on your power tool regularly. The
motor’s fan will draw the dust inside the housing and excessive accumulation of powdered metal may cause electrical hazards.
Products sold in GB only:
Your product is fitted with an BS 1363/A approved electric
plug with internal fuse (ASTA approved to BS 1362).
If the plug is not suitable for your socket outlets, it should be
cut off and an appropriate plug fitted in its place by an authorised customer service agent. The replacement plug
should have the same fuse rating as the original plug.
The severed plug must be disposed of to avoid a possible
shock hazard and should never be inserted into a mains
socket elsewhere.
u Always wait until the power tool has come to a com-
plete stop before placing it down.
u Secure the workpiece. A workpiece clamped with
clamping devices or in a vice is held more secure than by
hand.
Product description and
specifications
Read all the safety and general instructions.
Failure to observe the safety and general instructions may result in electric shock, fire
and/or serious injury.
Please observe the illustrations at the beginning of this operating manual.
Intended Use
The power tool is intended for dry sanding of wood, plastic,
metal, filler and varnished surfaces.
Power tools with electronic control are also suitable for polishing.
Product Features
The numbering of the product features refers to the diagram
of the power tool on the graphics page.
Accessories shown or described are not included with the
A)
product as standard. You can find the complete selection of
accessories in our accessories range.
A)
A)
Technical Data
Random orbit sandersGEX 125-1 A
Professional
Article number
3 601 C87 0..3 601 C87 5..
Orbital stroke rate preselection–●
Rated power inputW250250
No-load speed n
0
rpm12,0007500–12000
No-load orbital stroke raterpm24,00015,000–24,000
Bosch Power Tools1 609 92A 4AJ | (24.05.2018)
GEX 125-1 AE
Professional
8 | English
Random orbit sandersGEX 125-1 A
Professional
Orbit diametermm2.52.5
Sanding pad diametermm125125
Weight according to EPTA-Procedure 01:2014kg1.31.3
Protection class / II / II
The specifications apply to a rated voltage [U] of 230 V. For different voltages and models for specific countries, these values can vary.
GEX 125-1 AE
Professional
Assembly
u Pull the plug out of the socket before carrying out any
work on the power tool.
Selecting the Sanding Sheet
Different sanding sheets are available, depending on the material you are working with and the required surface removal rate:
MaterialApplicationGrit
– Paint
– Varnish
– Filler
– Bodyfiller
Expert for Wood
– All wood and wood-based ma-
terials (e.g. hardwood, softwood, chipboard, construction
boards)
Best for Wood
– Hardwood
– Chipboard
– Construction boards
– Metal materials
For sanding down paintCoarse40
For sanding undercoats (e.g. removing brushstrokes, paint drips and paint runs)
For final sanding of primers prior to paintingFine180
For pre-sanding, e.g. of rough and uneven
beams and boards
For surface sanding and levelling of slight irregularities
For finish-sanding and fine sanding of woodFine180
Medium80
100
120
240
320
400
Coarse40
Medium80
100
120
240
320
400
60
60
– Car paint
– Stone
– Marble
– Granite
– Ceramic
– Glass
– Perspex
– Fibreglass reinforced plastics
Changing the sanding sheet (see figure A)
To remove the sanding sheet (6), lift it from the side and pull
it from the sanding pad (5).
Remove dirt and dust from the sanding pad (5), e.g. with a
paintbrush, before attaching a new sanding sheet.
1 609 92A 4AJ | (24.05.2018)Bosch Power Tools
For pre-sandingCoarse80
For shaping and edge chamferingMedium100
120
For fine sanding during shapingFine180
240
320
400
Buffing and edge roundingVery fine600
1200
The surface of the sanding pad (5) is fitted with a hook-andloop fastening, allowing sanding sheets with a similar backing to be secured quickly and easily.
Press the sanding sheet (6) firmly onto the underside of the
sanding pad (5).
English | 9
To ensure optimum dust extraction, make sure that the
punched holes in the sanding sheet are aligned with the
drilled holes in the sanding pad.
The alignment aid that is in the tool box and shown in the figure enables easy alignment of the sanding sheet (6) on the
sanding pad (5). Place the sanding sheet into the alignment
aid with the hook-and-loop fastening facing upwards and
press the power tool with the sanding pad firmly onto it.
Selection of the Sanding Plate
The power tool can be fitted with sanding pads of various
hardnesses, depending on the application:
– Extra soft sanding pad: Suitable for polishing and sensit-
ive sanding, even on curved surfaces.
– Medium hard sanding pad: Suitable for all sanding work,
universal application.
– Hard sanding pad: Suitable for heavy sanding on flat sur-
Remove the sanding sheet or polishing tool. Unscrew the
four screws completely (7) and remove the sanding pad (5).
Attach the new sanding pad (5) and retighten the screws.
Note: When attaching the sanding pad, make sure that the
teeth of the catch mate with the recesses in the sanding pad.
Note: Damaged sanding pads must only be replaced by an
after-sales service centre authorised to work with Bosch
power tools.
Dust/chip extraction
The dust from materials such as lead paint, some types of
wood, minerals and metal can be harmful to human health.
Touching or breathing in this dust can trigger allergic reactions and/or cause respiratory illnesses in the user or in
people in the near vicinity.
Certain dusts, such as oak or beech dust, are classified as
carcinogenic, especially in conjunction with wood treatment
additives (chromate, wood preservative). Materials containing asbestos may only be machined by specialists.
– Use a dust extraction system that is suitable for the ma-
terial wherever possible.
– Provide good ventilation at the workplace.
– It is advisable to wear a P2 filter class breathing mask.
The regulations on the material being machined that apply in
the country of use must be observed.
u Avoid dust accumulation at the workplace. Dust can
easily ignite.
Self-generated dust extraction with dust box (see figure
C1–C4)
Place the dust box (3) onto the extraction outlet (8) until it
clicks into place.
You can easily check the filling level of the dust box (3)
through the transparent container.
To empty the dust box (3), rotate and pull it downwards.
Before opening the dust box (3), knock the dust box against
a firm surface as shown in the figure to loosen the dust from
the filter element.
Holding the dust box (3) firmly, flap the filter element (9)
upwards out of the way and empty the dust box. Use a soft
brush to clean the flaps of the filter element (9).
External dust extraction (see figure D)
Fit a dust extraction hose (10) onto the extraction outlet (8).
Connect the dust extraction hose (10) to an extractor. You
will find an overview of connecting to various dust extractors
at the beginning of these operating instructions.
The dust extractor must be suitable for the material being
worked.
When extracting dry dust that is especially detrimental to
health or carcinogenic, use a special dust extractor.
Operation
Starting Operation
u Pay attention to the mains voltage. The voltage of the
power source must match the voltage specified on the
rating plate of the power tool. Power tools marked
230 V can also be operated at 220 V.
u Products that are only sold in AUS and NZ: Use a resid-
ual current device (RCD) with a nominal residual current
of 30 mA or less.
Switching On/Off
u Make sure that you are able to press the On/Off switch
without releasing the handle.
To switch on the power tool, tilt the on/off switch (1) toward the right to the “I” position.
To switch off the power tool, tilt the on/off switch (1) toward the left to the “O” position.
Preselecting the orbital stroke rate (GEX 125-1 AE)
You can even preselect the orbital stroke rate during operation using the necessary orbital stroke rate preselection
thumbwheel (2).
1–2Low orbital stroke rate
3–4Medium orbital stroke rate
5–6High orbital stroke rate
Bosch Power Tools1 609 92A 4AJ | (24.05.2018)
10 | English
The required orbital stroke rate is dependent on the material
and the work conditions and can be determined using practical tests.
After working at a low orbital stoke rate for an extended
period, you should operate the power tool at the maximum
orbital stroke rate for approximately three minutes without
load to cool it down.
Sanding Plate Brake
An integrated sanding pad brake reduces the orbital stroke
rate when running without load to prevent scoring when the
power tool is placed on the workpiece.
If the no-load orbital stroke rate constantly increases over
time, this means that the sanding pad is damaged and must
be replaced, or that the sanding pad brake is worn. A worn
sanding pad brake must be replaced by an after-sales service centre authorised to work with Bosch power tools.
Working Advice
u Pull the plug out of the socket before carrying out any
work on the power tool.
u Always wait until the power tool has come to a com-
plete stop before placing it down.
u This power tool is not suitable for bench-mounted use.
It must not be clamped into a vice or fastened to a workbench, for example.
For fatigue-free work, you can hold the power tool from
above, from the side or from the front, depending on the application (see figure E).
Sanding Surfaces
Switch the power tool on, place the entire sanding surface
against the surface of the workpiece and apply moderate
pressure as you move the sander over the workpiece.
The material removal rate and sanding result are primarily
determined by the choice of sanding sheet, the preselected
orbital stroke rate level and the contact pressure.
Only immaculate sanding sheets achieve good sanding performance and make the power tool last longer.
Be sure to apply consistent contact pressure in order to increase the lifetime of the sanding sheets.
Excessively increasing the contact pressure will not lead to
increased sanding performance, rather it will cause more
severe wear of the power tool and of the sanding sheet.
Do not use a sanding sheet for other materials after it has
been used to work on metal.
Use only original Bosch sanding accessories.
Rough Sanding
Attach a coarse grit sanding sheet.
Apply only light pressure to the power tool so that it runs at a
higher orbital stroke rate and a higher material removal rate
is achieved.
Fine Sanding
Attach a fine grit sanding sheet.
You can reduce the sanding plate orbital stroke rate by
lightly varying the contact pressure or changing the orbital
stroke rate level; the random orbit motion will be retained.
Move the power tool with moderate pressure flat on the
workpiece in a circular motion or alternately along and
across it. Do not tilt the power tool in order to avoid sanding
through the workpiece, e.g. veneers.
Switch the power tool off after completing operation.
Polishing
For polishing weathered lacquers and redressing scratches
(e.g. acrylic glass), the power tool can be fitted with an appropriate polishing tool, e.g. lambswool bonnet, polishing
felt or polishing sponge (accessory).
Select a low orbital stroke rate (level 1–2) when polishing in
order to avoid heating up the surface excessively.
Apply the polish to an area slightly smaller than the area
which you intend to polish. Using the appropriate polishing
tool, work in the polish with either linear or circular movements and with moderate pressure.
Do not allow the polish to dry out on the surface; this may
damage the surface. Do not expose the surface which you intend to polish to direct sunlight.
Clean the polishing tool regularly to ensure good polishing
results. Wash the polishing tools with mild detergent and
warm water; do not use thinning agents.
Maintenance and Service
Maintenance and cleaning
u Pull the plug out of the socket before carrying out any
work on the power tool.
u To ensure safe and efficient operation, always keep
the power tool and the ventilation slots clean.
In order to avoid safety hazards, if the power supply cord
needs to be replaced, this must be done by Bosch or by a
customer service centre that is authorised to repair Bosch
power tools.
After-sales service and advice on using products
Our after-sales service can answer questions concerning
product maintenance and repair, as well as spare parts. You
can find exploded drawings and information on spare parts
at: www.bosch-pt.com
The Bosch product use advice team will be happy to help you
with any questions about our products and their accessories.
www.powertool-portal.de, the internet portal for tradespeople and DIY enthusiasts.
In all correspondence and spare parts orders, please always
include the 10‑digit article number given on the type plate of
the product.
Cambodia
Robert Bosch (Cambodia) Co., Ltd
Unit 8BC, GT Tower, 08th Floor, Street 169,
Czechoslovakia Blvd, Sangkat Veal Vong
Khan 7 Makara, Phnom Penh
Bosch Power Tool (China) Co. Ltd.
Bosch Service Center
567, Bin Kang Road
Bin Kang District
Hangzhou, Zhejiang Province
China 310052
Tel.: (0571) 8887 5566 / 5588
Fax: (0571) 8887 6688 x 5566# / 5588#
E-Mail: bsc.hz@cn.bosch.com
www.bosch-pt.com.cn
HK and Macau Special Administrative Regions
Robert Bosch Co. Ltd.
21st Floor, 625 King’s Road
North Point, Hong Kong
Customer Service Hotline: +852 2101 0235
Fax: +852 2590 9762
E-Mail: info@hk.bosch.com
www.bosch-pt.com.hk
India
Bosch Service Center
69, Habibullah Road, (Next to PSBB School), T. Nagar
Chennai–600077
Phone: (044) 64561816
Bosch Service Center Rishyamook
85A, Panchkuin Road
New Delhi–110001
Phone: (011) 43166190
Bosch Service Center
79, Crystal Bldg., Dr. Annie Besant Road, Worli
Mumbai–400018
Phone: (022) 39569936 / (022 )39569959 /
(022) 39569967 / (022) 24952071
Indonesia
PT Robert Bosch
Palma Tower 10th Floor
Jalan RA Kartini II-S Kaveling 6
Pondok Pinang, Kebayoran Lama
Jakarta Selatan 12310
Tel.: (21) 3005-5800
www.bosch-pt.co.id
Malaysia
Robert Bosch Sdn. Bhd.(220975-V) PT/SMY
No. 8A, Jalan 13/6
46200 Petaling Jaya
Selangor
Tel.: (03) 79663194
Toll-Free: 1800 880188
Fax: (03) 79583838
E-Mail: kiathoe.chong@my.bosch.com
www.bosch-pt.com.my
Pakistan
Robert Bosch Middle East FZE – Pakistan Liaison Office
2nd Floor Plaza # 10, CCA Block, DHA Phase 5
Lahore, 54810
Phone: +92(303)4444311
Email: Faisal.Khan@bosch.com
Philippines
Robert Bosch, Inc.
28th Floor Fort Legend Towers,
3rd Avenue corner 31st Street,
Fort Bonifacio, Global City,
1634 Taguig City
Tel.: (632) 8703871
Fax: (632) 8703870
www.bosch-pt.com.ph
Singapore
Powerwell Service Centre Ptd Ltd
Bosch Authorised Service Centre (Power Tools)
4012 Ang Mo Kio Ave 10, #01-02 TECHplace
Singapore 569628
Tel.: 6452 1770
Fax: 6452 1760
E-Mail: ask@powerwellsc.com
www.powerwellsc.com
www.bosch-pt.com.sg
Thailand
Robert Bosch Ltd.
Liberty Square Building
No. 287, 11 Floor
Silom Road, Bangrak
Bangkok 10500
Tel.: 02 6393111
Fax: 02 2384783
Robert Bosch Ltd., P. O. Box 2054
Bangkok 10501
www.bosch.co.th
Bosch Service – Training Centre
La Salle Tower Ground Floor Unit No.2
10/11 La Salle Moo 16
Srinakharin Road
Bangkaew, Bang Plee
Samutprakarn 10540
Tel.: 02 7587555
Fax: 02 7587525
Vietnam
Branch of Bosch Vietnam Co., Ltd in HCMC
Floor 10, 194 Golden Building
473 Dien Bien Phu Street
Ward 25, Binh Thanh District, Ho Chi Minh City
Tel.: (08) 6258 3690
Fax: (08) 6258 3692
Hotline: (08) 6250 8555
www.bosch-pt.com.vn
TOO “Robert Bosch” Power Tools, After Sales Service
Rayimbek Ave., 169/1
050050, Almaty, Kazakhstan
Bosch Power Tools1 609 92A 4AJ | (24.05.2018)
12 | English
Service Email: service.pt.ka@bosch.com
Official Website: www.bosch.com, www.bosch-pt.com
Bahrain
Hatem Al Juffali Technical Equipment Establishment.
Kingdom of Bahrain, Setra Highway, Al Aker Area
Phone: +966126971777-311
Fax: +97317704257
Email: h.berjas@eajb.com.sa
Egypt
Unimar
20 Markaz kadmat
El tagmoa EL Aoul – New Cairo
Phone: +20 2224 76091-95
Phone: +20 2224 78072-73
Fax: +20222478075
Email: adelzaki@unimaregypt.com
Iran
Robert Bosch Iran
3rd Floor, No 3, Maadiran Building
Aftab St., Khodami St., Vanak Sq.
Tehran 1994834571
Phone: +9821 86092057
Iraq
Sahba Technology Group
Al Muthana airport road
Baghdad
Phone: +9647901906953
Phone Dubai: +97143973851
Email: bosch@sahbatechnology.com
Jordan
Roots Arabia – Jordan
Nasser Bin Jameel street, Building 37 Al Rabiah
11194 Amman
Phone: +962 6 5545778
Email: bosch@rootsjordan.com
Kuwait
Al Qurain Automotive Trading Company
Shuwaikh Industrial Area, Block 1, Plot 16, Street 3rd
P.O. Box 164 – Safat 13002
Phone: 24810844
Fax: 24810879
E-mail: josephkr@aaalmutawa.com
El Naser for Workshop Tools
Swanee Road, Alfalah Area
Tripoli
Phone: +218 21 4811184
Oman
Malatan Trading & Contracting LLC
P.O. Box 131
Ruwi, 112 Sultanate of Oman
Phone: +968 99886794
Email: malatanpowertools@malatan.net
Qatar
International Construction Solutions W L L
P. O. Box 51,
Doha Phone: +974 40065458
Fax: +974 4453 8585
Email: csd@icsdoha.com
Saudi Arabia
Juffali Technical Equipment Co. (JTECO)
Kilo 14, Madinah Road, Al Bawadi District
Jeddah 21431
Phone: +966 2 6672222 Ext. 1528
Fax: +966 2 6676308
Email: roland@eajb.com.sa
Syria
Dallal Establishment for Power Tools
P.O. Box 1030
Aleppo
Phone: +963212116083
Email: rita.dallal@hotmail.com
United Arab Emirates
Central Motors & Equipment LLC, P.O. Box 1984
Al-Wahda Street – Old Sana Building
Sharjah
Phone: +971 6 593 2777
Fax: +971 6 533 2269
Email: powertools@centralmotors.ae
Yemen
Abualrejal Trading Corporation
Sana’a Zubiery St. Front to new Parliament Building
Phone: +967-1-202010
Fax: +967-1-279029
Email: tech-tools@abualrejal.com
Diesel & Autoelectric Service Ltd.
117 Nyerere Rd., P.O. Box 70839
Vingunguti 12109, Dar Es Salaam
Phone: +255 222 861 793/794
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: (01300) 307044
Fax: (01300) 307045
Inside New Zealand:
Phone: (0800) 543353
Fax: (0800) 428570
Outside AU and NZ:
Phone: +61 3 95415555
www.bosch-pt.com.au
www.bosch-pt.co.nz
Disposal
The power tool, accessories and packaging should be recycled in an environmentally friendly manner.
Do not dispose of power tools along with
household waste.