Kernlochbohrer DKB-352/S-PRO User manual

Operating instructions
Diamond core drill
DKB-352/S-PRO DKB-502/S-PRO
Kernlochbohrer GmbH
Geigersbühlweg 52
72663 Großbettlingen
Phone [phone]
E-mail: [e-mail] Version 0 2. Output 5/2023

Content
Introduction and description 3
About this guide 3
Thanks to the buyer 4
Explanation of symbols 4
Safety regulations 4
Technical data 8
Product description 9
Use and care 10
Precautions 10
Mounting and assembly of drill motor and stand 11
Changing drill bits 12
Drill and machine cooling 13
Electrical connection 13
Water supply connection 14
Speed selection 14
Drilling 15
Mechanical overload protection 16
Electronic overload protection 16
Overvoltage protection 17
Overheating - Thermal protection 18
Carbon brush warning system 18
Daily maintenance of the power tool 19
Maintenance and inspection plan 20
Troubleshooting 21
Environmental protection 23
Noise/Vibration 24
Warranty 24
Exploded view 25
EC Declaration of Conformity Attachment
2

Introduction and description
The core drilling equipment of the DKB-PRO series is intended for professional use
and may only be operated by instructed persons. Strictly adhere to the instructions
in the operating manual to avoid electric shock or fire.
Our company declines all responsibility in the event of violations of the operating
instructions that may lead to injuries or machine damage. In addition, all currently
applicable regulations of the Accident Prevention Regulations (UVV) and the
Employer's Liability Insurance Association (BG) must be observed.
In conjunction with the appropriate drill bits, the machine is intended for drilling
concrete, stone and masonry in wet cutting. The machine may only be used in
conjunction with the appropriate drill stand. Care must be taken to ensure that you
select the correct drill bit for the corresponding drilling technique in each case.
The machine may only be serviced by persons who have the appropriate
qualification and certification.
About this guide
These operating instructions are for the model
DKB-352/S-PRO
DKB-502/S-PRO
Check the machine model against the nameplate.
3

Thanks to the buyer
Thank you for purchasing a core drill of the DKB-PRO series from Kernlochbohrer
GmbH. Please read the operating instructions carefully and observe the safety
instructions. Through proper operation, you will fully appreciate the outstanding
performance of our products. Keep this manual in a safe place for future reference.
If you have any questions about the operation of the core drill, please contact the
core drill GmbH directly. We are available to answer your questions at any time.
Note:
Kernlochbohrer GmbH reserves the right to change the design and appearance of
the products and their operating instructions. Future changes to the operating
instructions will be made without prior notice.
Explanation of symbols
Warning from general Danger. Failure to follow these safety precautions and
instructions may result in electric shock, fire and/or serious injury.
Safety regulations
❖Read all precautions before start-up and keep the operating instructions. In
addition, all currently applicable Regulations the Accident prevention regulation
(UVV) and the Employer's Liability Insurance Association (BG) must be
observed.
❖Please follow the operating instructions carefully, as failure to follow these
safety precautions and instructions may cause electric shock, fire and/or
serious injury.
4

1. Keep your work area clean and well lit. Disorder or unlit work areas can lead to
accidents.
2. Do not work with the power tool near flammable liquids, gases or dust. Power
tools produce sparks that can ignite dust or fumes, causing explosions.
3. Keep children and other persons away while using the power tool. If you are
distracted, you may lose control of the tool.
4. Be attentive, work with concentration and pay attention to what you are doing.
Do not use a power tool when you are tired or under the influence of drugs,
alcohol or medication. A moment of inattention can result in serious injury.
5. Wear suitable protective equipment and always protective goggles. Wearing
suitable protective equipment such as a dust mask, non-slip safety shoes, hard
hat or hearing protection reduces the risk of injury.
6. Avoid unintentional starting of the machine. Make sure that the power tool is
switched off before connecting it to the power supply. If you have your finger on
the switch when carrying the power tool or connect the machine to the power
supply when it is switched on, this can lead to accidents.
7. Remove setting tools or wrenches before switching on the power tool. A tool or
wrench that is on a rotating device can cause injury.
5

8. Avoid unusual postures. Ensure a secure footing and maintain your balance at
all times. Do not work on a ladder. This will give you better control of the power
tool in unexpected situations.
9. Wear appropriate clothing. Do not wear loose clothing or jewelry. Keep hair,
clothing and gloves away from moving parts. Loose clothing, jewelry or long hair
can be caught by moving parts.
10. Do not overload the device. Use the appropriate power tool for your work. With
the appropriate power tool, you will work better and more gently in the specified
power range.
11. Do not use a power tool whose switch is damaged. A power tool that cannot be
switched on and off is dangerous and must be repaired.
12. Unplug the power tool from the wall outlet before making any device
adjustments, replacing accessories, or setting the power tool aside. This safety
measure prevents unintentional starting of the power tool.
13. Keep unused power tools out of reach of children. Do not allow persons to use
the device who are not familiar with it or have not read these instructions. Power
tools are dangerous when used by inexperienced persons.
14. Note that the voltage must not exceed +/-5% of the nominal voltage. Higher
voltages can cause irreparable damage. Note that higher voltage peaks are not
generated when operating the machine via a generator.
15. The plug of the power tool must match the socket. Do not change the plug
under any circumstances. Do not use adapter plugs with grounding-type forces.
Unmodified plugs and matching outlets reduce the risk of electric shock.
6

16. Avoid body contact with grounded surfaces or grounded components such as
pipes, radiators, stoves, and refrigerators.
17. Do not expose power tools to rain or wet conditions. Water entering a power
tool increases the risk of electric shock.
18. Never use the cord to carry or pull the power tool or to unplug the power tool
from the wall outlet. Keep it away from heat, oil, sharp edges or moving parts.
Damaged, crushed or twisted cables increase the risk of electric shock.
19. When using a power tool outdoors, use only an extension cord that is suitable
for outdoor use. Using a cord that is suitable for outdoor use reduces the risk of
electric shock. When using with an extension cord, also make sure that the
extension cord has the same cross-section as the cord on the machine.
20. The use of products such as cutters, grinders, drills that machine sand or other
materials can generate dust and fumes that may contain hazardous chemicals.
Check the type of material you are going to machine and use a suitable
respirator.
21. Non-approved spare parts and any modification are prohibited on our products.
22. If the operation of a power tool in a humid environment is unavoidable, use a
residual current circuit breaker. The use of a ground fault circuit interrupter
reduces the risk of electric shock.
23. If a vacuum cleaner and suction device are required, make sure they are
connected and used properly. The use of a vacuum cleaner can reduce dust-
related hazards.
7

Technical data
Model
DKB-352/S-PRO
DKB-502-/S-PRO
Item no.
6206
6211
Power
3300W
3500W
Voltage
230V
230V
Current
16A
16A
Weight
13.5kg / 13.7kg
14.0kg / 14.2kg
Frequency
50-60HZ
50-60HZ
Max drilling diameter
With stand
402mm (1. Aisle)
202mm (2. Aisle)
102 mm (3. Aisle)
502mm (1. Aisle)
302mm (2. Aisle)
162 mm (3. Aisle)
Speed
350/700/1100 1/min
250/500/750 1/min
Spindle thread
1-1/4" UNC & G1/2"
1-1/4" UNC & G1/2"
Compatible stands
KBS-352/M-PRO
KBS-502/M-PRO
Packing dimension
650x460x215mm
650x460x215mm
8

Product description
DKB-352/S-PRO and DKB-502/S-PRO
1. Display power range 5. LED display
2. Gear switch 1 / 2 / 3 6. On/Off switch
3. Carbon brushes 7. LED red and yellow light
4. Magnesium housing
The LED display shows the current temperature, amperage (A), voltage (V),
operating hours and warning indicators.
9
3
5
6
7
4
2
1

Use and care
Only use diamond core bits which are in a sharp and undamaged condition.
Properly maintained diamond core bits with sharp cutting segments do not get
bogged down so quickly and are easier to guide.
Use the power tool, accessories and drills, etc. in accordance with these operating
instructions, taking into account the working conditions and the work to be
performed. Using the power tool for operations other than its intended use could
result in a hazardous situation.
Have your power tool repaired only by qualified personnel and only with original
spare parts.
Precautions
1. ALWAYS wear hearing protection! When using drilling motors, the loud drilling
noise in the working area can cause hearing damage.
2. When drilling, keep a sufficient distance to the core drill and do not touch any
rotating parts. Protect the danger zone and keep children and other persons
away from it. Falling and splashing parts can cause injuries.
3. This diamond core drill is intended for professional use only and may only be
operated by trained personnel. The appropriate use of the core drill includes
drilling rock, reinforced concrete and masonry.Der Bohrmotor muss
regelmäßig (ca. alle 6 Monate) von einer zertifizierten Elektrofachkraft nach
VDE überprüft werden.
4. When used for overhead drilling, a functional water collection ring must be
used. Make sure that no water can get into the motor.
5. Switch off the core drill immediately if it stops for any reason. After you have
determined and eliminated the cause and performed a visual inspection of the
device and core bit, the core drill can be restarted.
10

Preparation
Subject the core drill to a brief visual inspection before each start. Also check
whether the network voltage corresponds to the voltage specified on the nameplate
of the tool.
Mounting and assembly of drill motor and stand
Make sure that the core drill rig is not attached to the drill stand before mounting the
drill stand.
The DKB-352/S-PRO and DKB- 502/S-PRO core drilling
machines may only be operated with a core drill rig.
Before inserting the drill motor into the drill stand, the
adapter plate must be attached to the drill motor. For
this purpose, use the 4 M-8 Allen screws, as well as the
supplied feather key.
Should you use our vacuum base plate VGP-420/PRO to fix the core drill rig, make
sure that the vacuum is at least -0.8bar and also make sure that the seal is not
worn or damaged.
Use an impact anchor together with a disk wing nut and
a cord threaded rod (optional fastening set) to fasten the
drill stand to the substrate. The disk wing nut should be
placed in the center of the drill stand. After mounting,
adjust the 4 leveling screws on the drill stand to achieve
a good leveling position. You can do this with the aid of
the level on the drill stand.
A water collection ring is strongly recommended for wet wells.
11

Changing drill bits
A diamond core bit is a cylinder which is equipped with brazed or laser welded
segments. There are 2 types of diamond core bits, wet drill bits and dry drill bits.
These usually have a 1 1/4UNC or an M16 female threaded connection. Our
DKB-352/S-PRO and DKB-502/S-PRO core drills can only perform wet drilling. The
drive spindles all have a 1 1/4UNC external and a G1/2 internal thread connection.
For easier removal of the drill bit, you can apply waterproof grease to the spindle
thread of the machine.
To mount a drill bit on the core drill, simply screw it onto
the drill spindle. With the aid of our supplied "quick-
change ring", you can loosen the core bit more easily.
Optionally, you can use a copper ring for this purpose.
Make sure that you have disconnected the mains plug from the mains before
changing drill bits or removing them.
The core drill and the drill bit are relatively heavy. For this reason, always wear
protective gloves to prevent the sharp tool from causing injury to your hand.
To change the drill bit, use a 32mm wrench on the drill
spindle and a 41mm wrench on the drill bit at the same
time.
Adapters are available as accessories for drills with
different internal threads.
After mounting the drill on the machine, run it briefly and check the radial runout of
the drill bit.
12

Drill and machine cooling
The gearbox of the drill motor has splash lubrication for cooling.
The diamond segments of the wet core bit are cooled with water.
The electric motor is air-cooled.
Electrical connection
To reduce the risk of electric shock and to protect the operator, the DKB-352/S-
PRO and DKB-502/S-PRO core drill must only be operated via a Portable Residual
Current Device, or PRCD personal circuit breaker.
After connecting to the power supply, first press the
"RESET" button on the PRCD circuit breaker to
energize the circuit to the core drill. In the event of a
voltage drop, the PRCD circuit breaker switches off and
must be switched on again as soon as the power supply
is restored. The fault current at which the PRCD circuit
breaker switches off is 10mA.
Never place or put the PRCD circuit breaker in water. Before starting work, check
for proper operation by pressing the TEST button on the PRCD circuit breaker.
Never operate the core drill directly from the mains power source without a PRCD
circuit breaker.
Water supply connection
To connect the water supply, attach the quick coupling to a water hose. Use only
clean water. The use of water that is contaminated will accelerate the process of
wear of the water seal ring.
The maximum water pressure must not exceed 3 bar.
The water serves as a coolant to prevent the drill bit from heating up excessively
during drilling.
13

Staub und Partikel, die sich beim Bohren bilden, können das Wasserversorgungs-
system verstopfen. Wenn nötig muss dies geprüft und gereinigt werden.
Optionally, a GARDENA plug can be used to connect a water hose directly or to
connect to a water tank with sufficient water pressure.
Never allow water to enter the motor. It could cause an electric shock.
There is a water seal between the housing and the drill spindle on the DKB-352/S-
PRO and DKB-502/S-PRO models. If water leaks from this seal, it must be
replaced immediately.
Speed selection
The DKB-352/S-PRO and the DKB-502/S-PRO is equipped with a mechanical 3-
speed oil bath gearbox.
Select the speed according to the drill diameter (see Technical data p.8).
Speed selection or gear change may only be performed
when the core drill is switched off. Turn the gear selector
either clockwise or counterclockwise to the desired
position until it is engaged. If necessary, turn the drill
spindle slightly with a wrench to facilitate the speed
change. In this case, disconnect the machine from the
power supply beforehand.
The maximum diameter and speeds indicated on the nameplate are based on an
average concrete hardness. The speed varies depending on the hardness of the
material. For reinforced concrete, please select a low gear to reduce the speed.
14

Drilling
Always switch on the machine without load.
After switching on, next open the water line valve.
When water flows from the center of the drill, you can carefully start drilling.
Increase the feed pressure as soon as the cutting depth reaches approx. 10mm.
Always keep an eye on the condition of the drill motor. If you notice that it starts to
smoke slightly or if you notice the smell of an electric motor, relieve the core drill by
withdrawing it from the core hole. Then continue drilling slowly and carefully. In this
way, you prevent the carbon brushes from burning off due to a prolonged overload
of the electric motor.
When you have almost reached the end of the through hole, please reduce the feed
pressure at this point until the drill bit exits at the other side.
There is vertical drilling and angle drilling. For angle drilling, use the angle
adjustment function of the drill stand.
If you have selected too high a speed when drilling or you are working with too high
a feed pressure, this can cause the drill to jam.
If, during the drilling process, you notice that the feed rate decreases while the
force remains the same and the water coming out of the borehole is clear and has
some metal splinters, you have encountered rebar. Reduce the pressure on the drill
bit to cut through this easily. You can increase the pressure again once you have
cut through the rebar.
Werden Holzbalken, dicker Asphalt oder Bitumen geschnitten, erhöht sich dadurch
die Stromzufuhr. In diesem Fall reduzieren Sie den Vorschub, um weiter zu bohren.
Wenn Sie tiefer bohren müssen, als die Nutzlänge ihres Bohrers es zulässt, kann
optional eine Bohrverlängerung eingesetzt werden.
15

Mechanical overload protection
This machine is equipped with a mechanical slip clutch to protect the operator and
the machine from excessive torque forces. If the drill suddenly jams in the hole, the
safety clutch disengages and the drill spindle stops.
Make sure that the load on the clutch is not more than max. 3-4 seconds. Unload
the machine immediately. Otherwise, the safety clutch may be destroyed due to the
high wear. Do not continue drilling if the slipping clutch has been triggered, reduce
the feed rate immediately and wait until the core bit has reached the desired speed
again.
Caution!
A worn clutch must be replaced immediately by a specialist at an authorized
workshop. Working with a worn slipping clutch can lead to serious injuries.
Electronic overload protection
There are 2 LED indicators on both our handheld drill
motors and our pedestal mount drill motor. If the core
drill is in an overload condition, the red LED will
illuminate to indicate to the operator that maximum
power has been reached. Immediately reduce the feed
rate until the red LED goes out.
In addition to the display of the power range, the
DKB-352/S-PRO and DKB-502/S-PRO is equipped with
an LCD display. Among other things, the amperage is
displayed in real time. As soon as the core drill enters an
overload condition, the overcurrent symbol and the
ALARM warning light up on the display together with the
red LED light at the bottom.
If the core drill is in overload condition for a long time, the machine switches off for
self-protection and the red LED remains lit. Disconnect the device from the power
supply. Carry out a visual inspection of the device.
Above the display there are 4 lights that indicate the power range in which optimal
drilling can be performed.
16

Overvoltage protection
The drill motor can absorb short-term voltage peaks of up to max. 260V. Higher
voltages can cause irreparable damage. Please note that if the machine is operated
with a generator, they do not exceed the maximum specified value.
If the overvoltage protection trips during operation of the DKB-352/S-PRO and
DKB-502/S-PRO core drill, please check the power source and change it if
necessary.
The LCD display of the DKB-352/S-PRO and DKB-502/S-PRO shows, among other
things, the voltage in real time. If the motor is in overvoltage condition, the
overvoltage symbol lights up on the display together with the ALARM warning. The
machine shuts down or cannot be started.
17

Overheating - Thermal protection
If the temperature of the drill motor becomes too high, the built-in thermal protection
switch in the machine responds. At the same time, the yellow LED light illuminates
and the motor switches off. If this happens, do not restart the motor immediately.
Always allow the motor to cool down first for approx. 2-3 min.
The LCD display of the DKB-352/S-PRO and DKB-502/S-PRO shows, among other
things, the temperature in real time. When the motor overheats and the max.
working temperature is reached, the heat-up symbol lights up on the display
together with the ALARM warning.
Carbon brush warning system
As soon as the carbon brushes have reached the end of their service life, the core
drill stops automatically to protect the motor from further damage.
The carbon brush warning system consists of 2 LED lights with one red and one
yellow LED. If both the red and yellow lights are on at the same time, you should
check the carbon brushes and replace them if necessary. Remember, always
replace them in pairs.
18

Daily maintenance of the power tool
1. Check if all screws and nuts are well tightened.
2. Check that the water seals are intact.
3. Check if the gearbox is tight or if oil is leaking.
4. Check if the PRCD circuit breaker is working properly.
5. Always keep all accessories and the machine clean and dry.
6. Pay attention to the carbon brushes. If they have reached the end of their
service life and/or both LED lights are on, replace them immediately. To
replace, first remove the cover of the carbon brush holder and pull the carbon
brush out of the holder. Then insert a new one and close the cover again.
Repeat the procedure with the other carbon brush on the opposite side of the
core drill.
7. Check the condition of the gear oil after the gear unit has reached approx. 300
working hours. If the gear oil is heavily contaminated, have the gear oil
replaced immediately by an authorized service center.
8. After finishing the work, remove the drill bit and then clean the entire machine.
Do not forget to lubricate the spindle thread. Keep the power tool out of reach
of children and in a dry environment.
9. Insulation resistance measurement. Use a 500V ohmmeter to measure the
insulation resistance between L1 (phase), N (neutral) and the housing. The
value must not be less than 7 MΩ.
19

Maintenance and inspection plan
Regular inspection according to the maintenance and inspection schedule is
urgently required. Shorten the intervals between maintenance if you use the
product very frequently.
Maintenance points
(regular inspection
required)
Each time
before use
In the first
month or
after 25
working
hours
In the
third
month or
after 50
hours of
work
Every
year or
after 200
working
hours
Leakage from the
gearbox seal
√
√
√
√
Leakage from the water
seals
√
√
√
√
Mains cable Visual
inspection
√
√
√
√
PRCD circuit breaker
√
√
√
√
General function test
－
－
√
√
Concentricity of the
drilling spindle
√
√
√
√
Abrasion on the drill
spindle
－
－
√
√
Mains switch Function
test
√
√
√
√
Drill spindle lubrication
√
√
√
√
Check the water valve
for free movement
√
√
√
√
Nuts and bolts
－
－
－
√
Carbon brushes
－
－
－
√
Gear oil
－
－
－
√
20