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Selection Guide For Screwdrivers; Impact Wrenches - Bosch 1375-01 Catalogue

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SELECTION GUIDE FOR SCREWDRIVERS.

Torque is a decisive parameter for
controlling the pretension force
Screwdrivers with adjustable cut-off clutch
applied. The table provides an over-
For screw connections with high torque accuracy
view of the recommended torques
Torque upper range limited by reaction torques
for common bolt and nut sizes. The
Further advantages: low noise, low wear, long service life,
recommended maximum torques
the user has no influence on the torque
apply to untreated, oil-lubricated
screws (coefficient of friction =
0.125). The torques correspond to
approx. 62 % of the yield point.

Impact Wrenches

For large screw / bolt diameters with high torque
Virtually free of reaction torque, therefore no upward limitation
Torque accuracy depending
Bolting event
on screwdriver system and
screwdriving type
The torque that can be achieved for
a screw connection depends on the
type of screwdriving / bolting situa-
tion. To achieve a balanced basis for
Rotation
assessment, all data on screwdrivers
is based on unbending, or "hard"
screw connections (30° angle of
rotation). In the case of flexible or
Rotation
"soft" screw connections, achievable
values are, in part, considerably
below the nominal values. Further-
more, torque variance increases. Due
Rotation
to the wide variety of possibilities,
specifications with absolute values
are not possible. If in doubt, use a
trial and error system. The table
Rotation
offers an overview of the advantages
and achievable torque accuracy of
the individual screwdriver systems
with various characteristic screw-
Rotation
driving applications.
Rotation
46
0 602 485 1..
0 602 488 1..
0 602 486 2..
0 602 489 0..
0 602 487 0..
0 602 442 0..
0 602 443 0..
0 602 440 0..
0 602 433 1..
0 602 438 0..
0 602 435 0..
0 602 439 0..
Torque accuracy
Torque accuracy
Torque accuracy
Angle of
with overload
with percussion
rotation
with automatic
disengaging clutch
mechanism
to M
max.
shut-off
d
very good
good to very good
satisfactory –
depending upon
up to
approx.
the degree of
30°
accuracy required
good to very good
good to
somewhat
up to
satisfactory
unsatisfactory
approx.
60°
good – provided
satisfactory
satisfactory –pro-
cut-out function
vided only a low
over 60°
is still operative
level of accuracy
is required
good – provided
satisfactory
satisfactory
cut-out function
is still operative
good – provided
good
satisfactory
angle of
cut-out function
rotation
is still operative
not
definable
good – provided
good – provided
good
cut-out function
that the function
is still operative
is still operative
Torque for hard screwdriving application as per ISO 5393 (Nm)
0,1
0,5
1
Tightening
torque
When you select a screwdriver, you
Guideline values for maximum
bolt/screw tightening torques in
must consider not only the re-
Nm. Assumed friction below head
quired torque – as a function of
m ges. = 0.12, calculated from the
the pretensioning force required
stressed cross sections: yield point
from the bolted connection – but
usage 90 %. Valid for shaft screws
also the torque accuracy as a func-
with standard metric thread as per
tion of the bolting event. This
DIN 13, BL 13; heads as per
information has been compiled in
DIN 931, 933.
tables 1 and 2 in order to facilitate
the selection from among the
various bolting systems. The fixed
torque values provided apply to
"hard" bolted connections. The
maximum values are lower for
"soft" bolted connections (e.g.
spring washers, rubber washers,
etc.)
5
10
50
100
Hardness
class per
8.8
DIN 267
M 2.5
0.7
M 3
1.2
M 4
2.9
M 5
5.5
M 6
9.7
M 8
23
M 10
47
M 12
80
M 14
130
M 16
196
M 18
270
M 20
385
M 22
510
M 24
650
M 27
960
M 30
1300
500
1000
10.9
1.0
1.7
4
8
13.6
33
65
113
180
275
380
540
715
910
1345
1830
47

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