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8-2. Inherent Drawbacks of Cordless Driver Drills Requiring Particular Attention During Sales Promotion
The cordless 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) The work which requires particularly strong torque should be conducted at low speed.
Instruct the customer that the work which requires particularly strong torque should be done at low speed.
Because it is easy to lock the motor at high speed.
(3) Do not insert a foreign object into body.
A foreign object inserted through a hole may cause a failure. Please instruct customers to never insert a
foreign object into body.
(4) 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.)
(5) Variation in amount of work possible per charge
Although the nominal chargeable capacity of the storage battery used with the Model DB 3DL is 1.5 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.
(6) Precautions in the use of HSS drill bits
For example, although the Model DB 3DL is designed for drilling capacities of 2 mm (5/64") in mild steel, this
capability is not as efficient as conventional electric power tools. In particular, the drill tends to become locked
when the drill bit penetrates through the material. For this reason, the customer should be cautioned to
reduce the thrust on the main body of the drill when drilling completely through the material to avoid locking
the tool. Repeated locking of the drill causes excessive current flow from the batteries which not only
decreases the amount of work possible per charge, but could also result in burning of the motor.
