Working Advice - Bosch GDS Professional 18 V-EC 250 Originalbetriebsanleitung

OBJ_BUCH-2279-003.book Page 14 Tuesday, September 6, 2016 2:31 PM
14 | English
Reversing the rotational direction (see figure B)
The rotational direction switch 6 is used to reverse the rota-
tional direction of the machine. However, this is not possible
with the On/Off switch 7 actuated.
Right rotation: For driving in screws and tightening nuts,
press the rotational direction switch 6 through to the left
stop.
Left rotation: For loosening and unscrewing screws and
nuts, press the rotational direction switch 6 through to the
right stop.
Switching On and Off
To start the machine, press the On/Off switch 7 and keep it
pressed.
To switch off the machine, release the On/Off switch 7.
Adjusting the Speed
The speed of the switched-on power tool can be variably ad-
justed, depending on how far the On/Off switch 7 is pressed.
Light pressure on the On/Off switch 7 results in a low rotation-
al speed. Further pressure on the switch results in an increase
in speed.

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.
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 Standard Screws/Bolts
according to DIN 267
M 6
M 8
M 10
M 12
M 14
M 16
M 18
M 20
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.
1 609 92A 2NW | (6.9.16)
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 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
– Lubrication conditions at the screw/bolt connection
The following application cases result accordingly:
– A hard seat is given for metal-to-metal screw applications
– A spring-loaded seat is given for metal-to-metal screw ap-
– A soft seat is given for screw applications, e. g., metal on
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.
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
81 110 135
115 155 190
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
–20 °C and 50 °C. As an example, do not leave the battery in
the car in summer.
together
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.
plications, however with the use of spring washers, disc
springs, studs or screws/nuts with conical seat as well as
when using extensions.
wood or when using lead washers or fibre washers as back-
ing.
total
5.8 6.8 8.8
6.02 7.22 9.7
14.6 17.5 23
29 35 47
50 60 80
79 95 130
122 147 196
180 215 290
255 305 410
= 0.12). As a control
10.9 12.9
13.6 16.2
33 39
65 78
113 135
180 215
275 330
405 485
580 690
Bosch Power Tools