Precautions Requiring Particular Attention During Sales Promotion - Hitachi DH 24DVA Technical Data And Service Manual

7-3. Precautions Requiring Particular Attention During Sales Promotion

The cordless hammer 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, in comparison with conventional AC type impact drills and
hammer drills, there are certain precautions which require particular attention. Salespersons must be thoroughly
familiar with the following points to properly advise the customer in the most efficient use of the tool.
(1) Appropriate drilling capacity of the Model DH 24DVA
The Model DH 24DVA is not capable of drilling several dozens of holes like a conventional AC type impact or
hammer drill because it is a cordless hammer drill powered by a battery. If the customer wishes to use the tool
to drill many holes in succession, please recommend that a spare battery should be kept available for use.
(2) Use thrust within the range of 10 to 15 kgf
Applying heavy thrust (pressure) on the tool, such as is possible with AC type impact and hammer drills, will
not accelerate the drilling speed. On the contrary, excessive pressure will reduce bit rotation and hammering
speed, and cause the storage battery to rapidly lose its charge.
(3) Variation in amount of work possible per charge
Although the nominal capacity of the storage batteries used with the Model DH 24DVA is 2.0 Ah, the actual
capacity may vary within the range of 1.8 to 2.2 Ah depending on the ambient temperature during use and
recharging, and the number of times the storage batteries have been discharged and recharged. It should
also 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 workpieces, sharpness of the drill
bits, etc.) and the operational skill of the user.
(4) Precautions in drilling with metal drill bits.
Although the Model DH 24DVA is designed for a drilling capacity of up to 13 mm in steel, its operational
capabilities are considerably less than those of conventional AC type impact drills. Especially when drilling
with a 13 mm drill bit for steel, 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 pressure on the main body of the
tool when drilling completely through the material to avoid locking the drill.
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