Hitachi DS 18DMR Service Manual page 23

(6) Precautions in the use of HSS Drill Bits
For example, although the Model DS 18DMR is designed for drilling capacities of 50 mm (2") in wood, and
13 mm (1/2") in aluminum and mild steel, this capability is not as efficient as conventional electric power tools.
In particular, when drilling through aluminum material with a 13 mm (1/2") 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.
(7) Securely tighten the sleeve of the keyless chuck.
The keyless chuck may slip during operation if the shape of the drill bit shank is cylindrical depending on the
surface conditions, materials, etc. Please instruct the customers to retighten the keyless chuck more securely
if the keyless chuck slips during operation. The holding force of the keyless chuck is increased as the
tightening force of the keyless chuck is increased. The Models DS 18DMR and DS 14DMR are equipped with
the locking device to prevent loosening of the keyless chuck. The sleeve makes noise when tightening or
loosening. This is because of the locking device and there is no problem.
(8) Avoid continuous use.
Although the Model DS 18DMR can bear continuous operation under certain conditions, operating conditions
are different depending on material of workpiece and sharpness of the drill bit in use. Please instruct the
customers to avoid continuous use of the Models DS 18DMR and DS 14DMR and take a pause about
15 minutes after a single charge operation as a guide.
--- 20 ---