Bosch Power Tools 1375-01, 1375A manual Selection Guide for Screwdrivers, Torque accuracy depending

SELECTION GUIDE FOR SCREWDRIVERS.

Torque for hard screwdriving application as per ISO 5393 (Nm)

0,1 0,5 1 5 10 50 100 500 1000

Torque is a decisive parameter for controlling the pretension force applied. The table provides an over- view of the recommended torques for common bolt and nut sizes. The recommended maximum torques apply to untreated, oil-lubricated screws (coefficient of friction = 0.125). The torques correspond to approx. 62% of the yield point.

Screwdrivers with adjustable cut-off clutch	0 602 485 1..
For screw connections with high torque accuracy
	0 602 488 1..
Torque upper range limited by reaction torques
Further advantages: low noise, low wear, long service life,	0 602 486 2..
the user has no influence on the torque
	0 602 489 0..
	0 602 487 0..
Impact Wrenches
	0 602 442 0..
For large screw / bolt diameters with high torque

0 602 443 0..

Virtually free of reaction torque, therefore no upward limitation

0 602 440 0..

0 602 433 1..

0 602 438 0..

0 602 435 0..

0 602 439 0..

Torque accuracy depending	Bolting event
on screwdriver system and
screwdriving type
The torque that can be achieved for
a screw connection depends on the	Torque
type of screwdriving / bolting situa-
tion. To achieve a balanced basis for	Rotation
assessment, all data on screwdrivers
is based on unbending, or “hard”	Torque
screw connections (30° angle of
rotation). In the case of flexible or	Rotation
“soft” screw connections, achievable
values are, in part, considerably	Torque
below the nominal values. Further-
more, torque variance increases. Due	Rotation
to the wide variety of possibilities,
	Torque
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	Torque
and achievable torque accuracy of
the individual screwdriver systems
with various characteristic screw-	Rotation
driving applications.	Torque
	Rotation

Angle of	Torque accuracy	Torque accuracy	Torque accuracy
rotation	with automatic	with overload	with percussion
to Md max.	shut-off	disengaging clutch	mechanism
	very good	good to very good	satisfactory –
up to			depending upon
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-
over 60°	cut-out function		vided only a low
	is still operative		level of accuracy
			is required
	good – provided	satisfactory	satisfactory
	cut-out function
	is still operative
angle of	good – provided	good	satisfactory
	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

Tightening torque

Guideline values for maximum bolt/screw tightening torques in Nm. Assumed friction below head mges. = 0.12, calculated from the stressed cross sections: yield point usage 90%. Valid for shaft screws with standard metric thread as per DIN 13, BL 13; heads as per DIN 931, 933.

When you select a screwdriver, you must consider not only the re- quired torque – as a function of the pretensioning force required from the bolted connection – but also the torque accuracy as a func- tion of the bolting event. This information has been compiled in 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.)

Hardness class per DIN 267

M 2.5

M 3

M 4

M 5

M 6

M 8

M 10

M 12

M 14

M 16

M 18

M 20

M 22

M 24

M 27

M 30

8.8

0.7

1.2

2.9

5.5

9.7

23

47

80

130

196

270

385

510

650

960

1300

10.9

1.0

1.7

4

8

13.6

33

65

113

180

275

380

540

715

910

1345

1830

46 47