Hitachi DS 12DVF2, Technical Data And Service Manual

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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) 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) 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 batteries used with the Models DS 14DVF2,

DS 12DVF2 and DS 9DVF2 are 1.4 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 DS 14DVF2 is designed for drilling capacities of 25 mm (1") in wood, and

15 mm (19/32") in aluminum, and 12 mm (15/32") in mild steel, this capability is not as efficient as

conventional electric power tools.  In particular, when drilling through aluminum material with a 15 mm (19/32")

drill bit, 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.