Hitachi DS10DFL Service Manual - Page 12

2. Inherent Drawbacks of Cordless Driver Drills Requiring Particular Attention During Sales Promotion The cordless driver drill offers many advantages, such as use in places where no power source is available, and easy operation since there is no power cord. However, any cordless tool has certain inherent drawbacks. Salespersons must be thoroughly familiar with these drawbacks in order to properly advise customers on the most efficient use of the tool. A. Suggestions and precautions on efficient use of the tool (1) Use the cordless driver drill for comparatively light work. Because cordless driver drills are battery driven, the motor output in these tools is relatively low compared to conventional electric power tools. Accordingly, these tools are not suitable for the continuous drilling of many holes in succession or drilling into particularly hard materials, both of which impose a heavy load. Salespersons should therefore recommend conventional electric power tools for such heavy work. (2) Do not insert a foreign object into the body. A foreign object inserted through a hole may cause failure. Please instruct customers to never insert a foreign object into the body. (3) Avoid "locking" of the motor. Locking of the motor will cause an overload current that could result in motor overheating and/or rapid deterioration of the battery. Salespersons should advise customers to immediately release the switch and stop operation in case the motor becomes locked. (A jammed drill bit can be disengaged from the workpiece material by setting the switch to reverse rotation or manually turning the main body of the tool.) (4) Variations in the amount of work possible per charge. Although the nominal chargeable capacity of the storage battery used with the Model DS 10DFL 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 battery has been recharged. Note that other factors affecting the amount of work possible per charge are the working conditions (e.g., ambient temperature, type and moisture content of the workpiece, sharpness of the drill bit) and operational skill of the user. (5) Precautions on using HSS Drill Bits. Although the Model DS 10DFL is designed for drilling capacities of 21 mm (13/16") in wood, 12 mm (15/32") in aluminum, and 10 mm (3/8") in mild steel, these capabilities are not as efficient as those of conventional electric power tools. In particular, when drilling through aluminum material with a 12-mm (15/32") drill bit, the drill tends to become locked when the drill bit penetrates the material. For this reason, customers should be cautioned to reduce the thrust on the main drill body when drilling completely through a material in order to prevent the tool from locking. Repeated locking of the drill causes excessive current to flow from the battery, which not only decreases the amount of work possible per charge, but could also result in motor overheating. B. Suggestions and precautions on efficient use of the charger and storage battery If the Type BCL 1015 storage battery is exposed to direct sunlight for an extended period or the tool has just been operated for a long time, recharging may not be possible at a battery temperature above 50°C (122°F). In such case, customers should be advised to place the battery in a shaded area with good airflow, and allow sufficient cooling before recharging. This phenomenon is common to all existing batteries and chargers that employ temperature-sensitive overcharge protection devices. The cooling time necessary before recharging varies from a few minutes to about 40 minutes, depending on the load, duration of use, and ambient temperature. -9-