Practical advice
- Only apply the power tool to the screw/nut when the tool is switched off. Rotating tool inserts can slip off.
- Always secure application tools to the square drive with a locking pin or the retaining ring.
The torque depends on the impact duration. The maximum achieved torque results from the sum of all individual torques achieved through impact. Maximum torque is achieved after an impact duration of 6–10 seconds. After this duration, the tightening torque increases only minimally.
The impact duration is to be determined for each required tightening torque. The tightening torque actually achieved should always be checked with a torque wrench.
Screw applications with hard, spring-loaded or soft seats
When the achieved torques in an impact series are measured during a test and transferred onto a diagram, the result is the curve of a torque characteristic. The height of the curve corresponds to the maximum achievable torque, and the steepness indicates the duration in which this is achieved.
A torque characteristic 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
Consequently, the following applies in each case:
- A hard seat is used for metal-to-metal screw applications that use washers. After a relatively short impact duration, the maximum torque is achieved (steep characteristic curve). An unnecessarily long impact duration only causes damage to the machine.
- A spring-loaded seat is used for metal-to-metal screw applications that use spring lock washers, disc springs, studs or screws/nuts with conical seats. It is also called a spring-loaded seat when extensions are used.
- A soft seat is used for screw applications of e.g. metal on wood or screw applications that use 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. A much longer impact duration is also required.
Guide values for maximum screw tightening torques
Figures given in Nm; calculated from the tensional cross-section; utilisation 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 | Standard screws/bolts | High-strength bolts | ||||||
|---|---|---|---|---|---|---|---|---|
3.6 | 4.6 | 5.6 | 5.8 | 6.8 | 8.8 | 10.9 | 12.9 | |
M6 | 2.71 | 3.61 | 4.52 | 6.02 | 7.22 | 9.7 | 13.6 | 16.2 |
M8 | 6.57 | 8.7 | 11 | 14.6 | 17.5 | 23 | 33 | 39 |
M10 | 13 | 17.5 | 22 | 29 | 35 | 47 | 65 | 78 |
M12 | 22.6 | 30 | 37.6 | 50 | 60 | 80 | 113 | 135 |
M14 | 36 | 48 | 60 | 79 | 95 | 130 | 180 | 215 |
M16 | 55 | 73 | 92 | 122 | 147 | 196 | 275 | 330 |
M18 | 81 | 110 | 135 | 180 | 215 | 290 | 405 | 485 |
M20 | 115 | 155 | 190 | 255 | 305 | 410 | 580 | 690 |
Tips
Before screwing larger, longer screws into hard materials, it is advisable to pre-drill a pilot hole with the core diameter of the thread to approx. 2/3 of the screw length.
Note: Ensure that no metal particles enter the power tool.
After working at a low speed for an extended period, you should operate the power tool at the maximum speed for approximately three minutes without load to cool it down.
Recommendations for optimal handling of the battery
Protect the battery against moisture and water.
Only store the battery within a temperature range of -20 to 50 °C. Do not leave the battery in your car in the summer, for example.
A significantly reduced operating time after charging indicates that the battery has deteriorated and must be replaced.
Follow the instructions on correct disposal.
Belt clip
You can use the belt clip (3) to hang the power tool on a belt, for example. You then have both hands free and the power tool is always at hand.