NEC V28 0799-20 User Manual

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1.  To attach a socket or other accessory, 
align the hole in the accessory with 
the detent pin on the drive shank. 
Hold the detent pin in while pushing 
the socket onto the drive shank. The 
detent pin will snap into place in the hole 
to secure the socket.
2.  To remove the accessory, insert a nail 
or other thin object into the hole in the 
accessory and press the detent pin in. 
Pull the accessory off the drive shank.
Attaching and Removing Accessories 
(Cat. No. 0799-20, or other Impact Wrenches  
using the Quick Change 1/2” Square Drive 
to 7/16” Hex Adapter)
Cat. No. 0799-20 and accessory Cat. No. 
48-66-0061 are intended for use with drill 
bits and adapters with a 7/16” Hex Quick. 
The Quick Change shank has a ball-retainer 
groove. It is not intended for use with Hex 
Shank Bit Extensions.
1.  To attach an accessory, pull the chuck 
collar forward and insert the accessory 
shank. Release the collar. It may be 
necessary to pull the bit out slightly to 
engage the holding mechanism.
2. 
To remove the accessory, pull the chuck 
collar forward and remove the acces-
sory. Release the collar.
Fig. 3
Ball retainer 
groove
Open (Release)
Closed (Locked)
 WARNING
To reduce the risk of injury, keep 
hands away from the bit and all mov-
ing parts. Always wear safety goggles 
or glasses with side shields.
OPERATION
Using the Forward/Reverse Switch 
The forward/reverse switch may be set to 
three positions: forward, reverse and lock. 
Due to a lockout mechanism, the forward/
reverse switch can only be adjusted when 
the trigger is not depressed. Always al-
low the motor to come to a complete stop 
before using the forward/reverse switch.
1. For 
forward  (clockwise) rotation, 
push the forward/reverse switch 
in the direction shown. Check the 
direction of rotation before use.
2.  F o r  
r e v e r s e   ( c o u n t e r c l o c k w i s e ) 
rotation, push the forward/reverse 
switch in the direction shown. Check the 
direction of rotation before use.
3. To 
lock the trigger, push the forward/
reverse switch to the center position. 
The trigger will not work when the 
forward/reverse switch is in the 
locked position. Always lock the 
trigger or remove the battery pack 
before performing maintenance, chang-
ing accessories, storing the tool and any 
time the tool is not in use.
 WARNING
To reduce the risk of injury, only 
grasp tool by handle and red 
insulated surfaces (Fig. 5). Do 
not hold gray gear case when 
impacting or drilling.
 WARNING
To reduce the risk of explosion, 
e l e c t r i c   s h o c k   a n d   p r o p e r t y 
damage, always check the work area 
for hidden pipes and wires before 
drilling.
Starting, Stopping and Controlling 
Speed
This impact wrench may be operated at any 
speed from 0 to full speed.
1. To 
start the tool, grasp the handle fi rmly 
and pull the trigger.  
2. To 
vary the speed, increase or 
decrease the pressure on the trigger. 
The further the trigger is pulled, the 
greater the speed. 
3. To 
stop the tool, release the trigger. 
Fig. 4
 Reverse
Forward
Forward/
Reverse 
switch
Fig. 5
Impacting Techniques
The longer a bolt, screw, or nut is impacted, 
the tighter it will become. To help prevent 
damaging the fasteners or workpieces, 
avoid excessive impacting. Be particularly 
careful when impacting smaller fasteners 
because they require less impacting to reach 
optimum torque.
Practice with various fasteners, noting the 
length of time required to reach the desired 
torque. Check the tightness with a hand-
torque wrench. If the fasteners are too tight, 
reduce the impacting time. If they are not 
tight enough, increase the impacting time.
Impacting for two seconds is generally 
suffi cient for a 3/8" bolt and one second 
for a 5/16" bolt. However, oil, dirt, rust or 
other matter on the threads or under the 
head of the fastener affects the degree of 
tightness.
The torque required to loosen a fastener 
averages 75% to 80% of the tightening 
torque, depending on the condition of the 
contacting surfaces. However, if rust or 
corrosion causes seizing, more torque may 
be required.
On light gasket jobs, run each fastener down 
to a relatively light torque and use a hand 
torque wrench for fi nal tightening.
Electric Brake
The electric brake engages when the 
trigger is released, causing the socket 
to stop and allowing you to proceed with 
your work. Generally, the socket stops 
within two seconds. However, there may 
be a delay between the time you release 
the trigger and when the brake engages. 
Occasionally the brake may miss completely. 
If the brake misses frequently, the impact 
wrench needs servicing by an authorized 
MILWAUKEE service facility.