Bosch GDR Professional 14,4 V-EC Manual Original página 18

OBJ_BUCH-2047-002.book Page 18 Wednesday, November 2, 2016 3:55 PM
18 | English
Preselecting the Speed/Impact Frequency
With the button 6 you can preselect the required speed/im-
pact rate in three stages. Press the button 6 repeatedly until
the desired setting appears in the speed indicator 7. The se-
lected setting will be saved.
The required speed/impact frequency depends on the mate-
rial and the working conditions, and can be determined
through practical testing.
Switching the "PowerLight" On/Off
To switch the "PowerLight" 11 on, press button 8. To switch
the "PowerLight" 11 off, press button 8 again.
Working Advice
 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 dura-
tion, 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
When in a test, the achieved torques in an impact series are
measured and transferred into a diagram, resulting in the
Reference Values for Maximum Screw/Bolt Tightening Torques
Calculated from the tensional cross-section; utilization of the yield point 90 % (with friction coefficient μ
measure, always check the tightening torque with a torque wrench.
Property Classes accord- Standard Screws/Bolts
ing to DIN 267
3.6
M 6 2.71
M 8 6.57
M 10 13
M 12 22.6
M 14 36
M 16 55
Tips
Before screwing larger, longer screws into hard materials, it is
advisable to predrill a pilot hole with the core diameter of the
2
thread to approx. / of the screw length.
3
Note: Pay attention that no metal particles enter the power
tool.
Belt Clip
With the belt clip 3, the machine can be hung onto a belt. The
user has both hands free and the machine is always at hand.
Recommendations for Optimal Handling of the Battery
Protect the battery against moisture and water.
Store the battery only within a temperature range between
0 °C and 50 °C. As an example, do not leave the battery in the
car in summer.
1 609 92A 2CU | (2.11.16)
curve of a torque characteristic. The height of the curve corre-
sponds with the maximum reachable torque, and the steep-
ness indicates the duration in which this is achieved.
A torque gradient depends on the following factors:
– Strength properties of the screws/nuts
– 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 du-
ration, the maximum torque is reached (steep characteris-
tic curve). Unnecessary long impact duration only causes
damage to the machine.
– A spring-loaded seat is given for metal-to-metal screw ap-
plications, 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 back-
ing.
For a spring-loaded seat as well as for a soft seat, the maxi-
mum tightening torque is lower than for a hard seat. Also, a
clearly longer impact duration is required.
4.6 5.6 4.8 6.6
3.61 4.52 4.8 5.42
8.7 11 11.6 13.1
17.5 22 23 26
30 37.6 40 45
48 60 65 72
73 92 98 110
Occasionally clean the venting slots of the battery using a soft,
clean and dry brush.
A significantly reduced working period after charging indi-
cates that the battery is used and must be replaced.
Observe the notes for disposal.
Maintenance and Service
Maintenance and Cleaning
 Before any work on the machine itself (e. g. mainte-
nance, 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.
= 0.12). As a control
total
High-strength Bolts
5.8 6.8 6.9 8.8
6.02 7.22 8.13 9.7
14.6 17.5 19.7 23
29 35 39 47
50 60 67 80
79 95 107 130
122 147 165 196
10.9 12.9
13.6 16.2
33 39
65 78
113 135
180 215
275 330
Bosch Power Tools