John Deere ET-3103-J - Manual (Page 19)

Cordless Impact Wrench Operator's Manual 19
OPERATION CAUTIONS:
Operation
1. Resting the unit after continuous work:
After use for continuous bolt-tightening work, rest the unit for 15 minutes or so
when replacing the battery. The temperature of the motor, switch, etc., will rise if
the work is started again immediately after battery replacement, eventually
resulting in burnout.
CAUTION: DO NOT TOUCH THE PROTECTOR, AS IT GETS
VERY HOT DURING CONTINUOUS WORK.
2. 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.
3. Tightening torque:
Refer to Fig. 16 for the tightening torque of bolts (according to size), under the
conditions shown in Fig. 17. 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. 18 shows
an example of the relationship between tightening torque and the number of
tightening. As shown, tightening torque gradually weakens with the increase in
the number of tightening. 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.
NOTE: If a long striking time is used, screws will be strongly tightened. This
may cause the screw to break, or may damage the end of the bit. If the unit is
held at an angle to the screw being tightened, the head of the screw may be
damaged, or the specified torque may not be transmitted to the screw. Always
keep the unit and the screw being tightened in a straight line.
4. Use a tightening time suitable for the screw:
The appropriate torque for a screw differs according to the material and size of the
screw, and the material being screwed etc., so please use a tightening time
suitable for the screw. In particular, if a long tightening time is used in the case of
screws smaller than 5/16" (8 mm), there is a danger of the screw breaking, so
please confirm the tightening time and the tightening torque beforehand.
5. 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
operation time. Use the correct operating time for the bolt.
6. 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.