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8-2. Inherent Drawbacks of Cordless Impact Driver Drills Requiring Particular Attention during Sales
Promotion
The cordless impact driver drill offers many advantages; it can be used in places where no power source is
available, the absence of a cord allows easy use, etc. However, any cordless tool has certain inherent
drawbacks. Salespersons must be thoroughly familiar with these drawbacks in order to properly advise the
customer in the most efficient use of the tool.
A. Suggestions and precautions for the efficient use of the tool
(1) Use the Cordless Driver Drill for comparatively light work.
Because they are battery driven, the output of the motor in cordless driver drills is rather low in comparison
with conventional electric power tools. Accordingly, they are not suitable for continuous drilling of many holes
in succession, or for drilling into particularly hard materials which creates a heavy load. Salespersons should
recommend conventional electric power tools for such heavy work.
(2) Drilling of large diameter holes should be conducted at low speed.
Instruct the customer that drilling of large diameter holes or other work which requires particularly strong
torque should be done at low speed. Because there is less torque at high speed, attempting such work at high
speed will not improve working efficiency.
(3) Do not insert a foreign object into body vent holes.
The body of this tool has vent holes for improving the cooling efficiency. As a fan is built into the motor, a
foreign object inserted through a vent hole may cause a failure. Please instruct customers to never insert a
foreign object into the vent hole.
(4) Use at thrust of 100 to 150 N (10 to 15 kgf, 22 to 23 lbs.).
It would not accelerate the drilling speed of this unit to press the tool strongly against the workpiece as is done
with a usual AC impact drill. It whould instead damage the drill bit, resulting not only in a poorer working
efficiency but could also cause burning out of the motor.
(5) Avoid "Locking" of the motor.
Locking of the motor will cause an overload current that could result in burning of the motor and/or rapid
deterioration of the battery. Salespersons should advise the customer to immediately release the switch and
stop operation if the motor becomes locked. (A jammed drill bit can be disengaged from the workpiece
material by setting the switch to reverse rotation, or by manually turning the main body of the tool.)
(6) Variation in amount of work possible per charge
Although the nominal chargeable capacity of the storage batteries used with the Model DV 18DMR and
DV 14DMR is 2.0 Ah, 2.6 Ah or 3.0 Ah, the actual capacity may vary within 10% of that value depending on the
ambient temperature during use and charging, and the number of times the batteries have been recharged. It
should be noted that other factors which may have a bearing on the amount of work possible per charge are
the working conditions (ambient temperature, type and moisture content of the workpiece, sharpness of the
drill bit, etc.) and the operational skill of the user.
