622350

Hitachi WR8DH Manual

11
Zoom out
Zoom in
Previous page
1/54
Next page
10
English
3. Work at a tightening torque suitable for the bolt
under impact
The optimum tightening torque for nuts or bolts
differs with material and size of the nuts or bolts.
An excessively large tightening torque for a small
bolt may stretch or break the bolt. The tightening
torque increases in proportionate to the operaton
time. Use the correct operating time for the bolt.
4. Holding the tool
Hold the impact wrench firmly with both hands. In
this case hold the wrench in line with the bolt.
It is not necessary to push the wrench very hard.
Hold the wrench with a force just sufficient to
counteract the impact force.
5. Confirm the tightening torque
The following factors contribute to a reduction of
the tightening torque. So confirm the actual
tightening torque needed by screwing up some
bolts before the job with a hand torque wrench.
Factors affecting the tightening torque are as follows.
(1) Voltage
When the discharge margin is reached, voltage
decreases and tightening torque is lowered.
(2) Operating time
The tightening torque increases when the operating
time increases. But the tightening torque does not
increase above a certain value even if the tool is
driven for a long time. (See Fig. 12, 13 and 14)
OPERATIONAL CAUTIONS
1. Cautions on use of the speed control switch
This switch has a built-in, electronic circuit which
steplessly varies the rotation speed. Consequently,
when the switch trigger is pulled only slightly (low
speed rotation) and the motor is stopped while
continuously driving in screws, the components of
the electronic circuit parts may overheat and be
damaged.
2. Tightening torque
Refer to Fig. 12, 13 and 14 for the tightening torque
of bolts (according to size), under the conditions
shown in Fig. 15. Please use this example as a
general reference, as tightening torque will vary
according to tightening conditions.
Tightening torque varies, depending on the battery’s
charge level. Fig. 16 shows an example of the
relationship between tightening torque and the
number of tightenings, for a M14 × 50 high tension
bolt. As shown, tightening torque gradually weakens
with the increase in the number of tightenings. In
particular, as the torque decreases very close to the
complete discharge (“a” margin in graph), the unit’s
impact weakens, the number of time impacts
declines and tightening torque drops off abruptly.
If this occurs, check torque level, then recharge the
battery if necessary.
M14 × 50 High tensile bolt (tightening time 3 sec)
Tightening torque
Number of tightenings (PCS)/charging
Fig. 16
a
0 20 40 60 80 100 120
0
400
800
1200
Kg-cm
When full recharged
When completely discharged
Explanation of strength grade:
4 — Yield point of bolt: 32 kgf/mm
2
8 — Pulling strength of bolt: 40 kgf/mm
2
*The following bolt is used.
Ordinary bolt: Strength grade 4.8
High tensile bolt: Strength grade 12.9
)(
Bolt
Nut Fig. 15
Steel plate thickness t
… 11 …


Need help? Post your question in this forum.

Forumrules


Report abuse

Libble takes abuse of its services very seriously. We're committed to dealing with such abuse according to the laws in your country of residence. When you submit a report, we'll investigate it and take the appropriate action. We'll get back to you only if we require additional details or have more information to share.

Product:

For example, Anti-Semitic content, racist content, or material that could result in a violent physical act.

For example, a credit card number, a personal identification number, or an unlisted home address. Note that email addresses and full names are not considered private information.

Forumrules

To achieve meaningful questions, we apply the following rules:

Register

Register getting emails for Hitachi WR8DH at:


You will receive an email to register for one or both of the options.


Get your user manual by e-mail

Enter your email address to receive the manual of Hitachi WR8DH in the language / languages: English, German, Dutch, French, Italian, Spanish as an attachment in your email.

The manual is 0,59 mb in size.

 

You will receive the manual in your email within minutes. If you have not received an email, then probably have entered the wrong email address or your mailbox is too full. In addition, it may be that your ISP may have a maximum size for emails to receive.

The manual is sent by email. Check your email

If you have not received an email with the manual within fifteen minutes, it may be that you have a entered a wrong email address or that your ISP has set a maximum size to receive email that is smaller than the size of the manual.

The email address you have provided is not correct.

Please check the email address and correct it.

Your question is posted on this page

Would you like to receive an email when new answers and questions are posted? Please enter your email address.



Info