Working Advice; Maintenance And Cleaning; Warranty - Bosch Professional GDR 120-LI Original Instructions Manual

22
| English

Working Advice

u Apply the power tool to the screw/nut only when it is
switched off. Rotating tool inserts can slip off.
The torque depends on the impact duration. The maximum
achieved torque results from the sum of all individual torques
achieved through impact. The maximum torque is achieved
after an impact duration of 6–10 seconds. After this
duration, the tightening torque is increased only minimally.
The impact duration is to be determined for each required
tightening torque. The actually achieved tightening torque
is always to be checked with a torque wrench.
Screw Applications with Hard, Spring-loaded or Soft Seat
A test in which the achieved torques in an impact series are
measured and transferred to a diagram will produce the
curve of a torque characteristic. The height of the curve
corresponds with the maximum reachable torque, and the
steepness indicates the duration in which this is achieved.
A torque gradient depends on the following factors:
– Strength properties of the screws/nuts
Reference Values for Maximum Screw/Bolt Tightening Torques
Calculated from the tensional cross-section; utilization of the yield point 90 % (with friction coefficient μtotal = 0.12). As a
control measure, always check the tightening torque with a torque wrench.
Property Classes
according to DIN 267
M 6
M 8
M 10
M 12
M 14
M 16
Tips
Before screwing larger, longer screws into hard materials, it
is advisable to predrill a pilot hole with the core diameter of
2
the thread to approx. / of the screw length.
3
Note: Pay attention that no metal particles enter the power
tool.
Recommendations for Optimal Handling of the Battery
Protect the battery against moisture and water.
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.
Occasionally clean the venting slots of the battery using a
soft, clean and dry brush.
A significantly reduced working period after charging
indicates that the battery is used and must be replaced.
Observe the notes for disposal.
1.600.A00.X5J | 04.2016
Standard Screws/Bolts
3.6 4.6 5.6
2.71 3.61 4.52
6.57 8.7 11
13 17.5 22
22.6 30 37.6
36 48 60
55 73 92
– Type of backing (washer, disc spring, seal)
– Strength properties of the material being screwed/bolted
together
– Lubrication conditions at the screw/bolt connection
The following application cases result accordingly:
– A hard seat is given for metal-to-metal screw applications
with the use of washers. After a relatively short impact
duration, the maximum torque is reached (steep
characteristic curve). Unnecessary long impact duration only
causes damage to the machine.
– A spring-loaded seat is given for metal-to-metal screw
applications, however with the use of spring washers, disc
springs, studs or screws/nuts with conical seat as well as
when using extensions.
– A soft seat is given for screw applications, e. g., metal on
wood or when using lead washers or fibre washers as
backing.
For a spring-loaded seat as well as for a soft seat, the
maximum tightening torque is lower than for a hard seat.
Also, a clearly longer impact duration is required.
4.8 6.6 5.8
4.8 5.42 6.02
11.6 13.1 14.6
23 26 29
40 45 50
65 72 79
98 110 122

Maintenance and Cleaning

u 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 danger of injury when
unintentionally actuating the On/Off switch.
u For safe and proper working, always keep the
machine and ventilation slots clean.

Warranty

We provide warranty for Bosch tools in accordance to
legal provisions as specified in the warranty certificate
(verification through invoice and completed warranty
certificate).
Damages resulting from natural wear, overload or incorrect
use shall not be covered by warranty.
In the event of warranty claim, the machine must be sent,
assembled, to an Authorized Bosch Electrical Tools Technical
Support. Check our consumer support service (S.A.C.).
High-strength Bolts
6.8 6.9 8.8
7.22 8.13 9.7
17.5 19.7 23
35 39 47
60 67 80
95 107 130
147 165 196
Bosch Power Tools
10.9 12.9
13.6 16.2
33 39
65 78
113 135
180 215
275 330