Makita BDF450 Instruction Manual Download Page 8

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CAUTION:

• Make sure that the driver bit is inserted straight in the

screw head, or the screw and/or bit may be damaged.

NOTE:

• When driving wood screws, predrill pilot holes to make

driving easier and to prevent splitting of the workpiece.
See the chart.

Drilling operation

First, turn the adjusting ring so that the pointer points to
the marking. Then proceed as follows.

Drilling in wood

When drilling in wood, the best results are obtained with
wood drills equipped with a guide screw. The guide screw
makes drilling easier by pulling the bit into the workpiece.

Drilling in metal

To prevent the bit from slipping when starting a hole, make
an indentation with a center-punch and hammer at the
point to be drilled. Place the point of the bit in the indenta-
tion and start drilling.
Use a cutting lubricant when drilling metals. The excep-
tions are iron and brass which should be drilled dry.

CAUTION:

• Pressing excessively on the tool will not speed up the

drilling. In fact, this excessive pressure will only serve
to damage the tip of your bit, decrease the tool perfor-
mance and shorten the service life of the tool.

• There is a tremendous force exerted on the tool/bit at

the time of hole break through. Hold the tool firmly and
exert care when the bit begins to break through the
workpiece.

• A stuck bit can be removed simply by setting the

reversing switch to reverse rotation in order to back
out. However, the tool may back out abruptly if you do
not hold it firmly.

• Always secure small workpieces in a vise or similar

hold-down device.

• If the tool is operated continuously until the battery car-

tridge has discharged, allow the tool to rest for 15 min-
utes before proceeding with a fresh battery.

MAINTENANCE

CAUTION:

• Always be sure that the tool is switched off and the bat-

tery cartridge is removed before attempting to perform
inspection or maintenance.

Replacing carbon brushes

Replace when they wear down to the limit mark. Keep the
carbon brushes clean and free to slip in the holders. Both
carbon brushes should be replaced at the same time. Use
only identical carbon brushes.

(Fig. 10)

Use a screwdriver to remove two screws then remove the
rear cover.

(Fig. 11)

Raise the arm part of the spring and then place it in the
recessed part of the housing with a slotted bit screwdriver
of slender shaft or the like.

(Fig. 12)

Use pliers to remove the carbon brush caps of the carbon
brushes. Take out the worn carbon brushes, insert the
new ones and replace the carbon brush caps in reverse.

(Fig. 13)

Make sure that the carbon brush caps have fit into the
holes in brush holders securely.

(Fig. 14)

Reinstall the rear cover and tighten two screws securely.
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be per-
formed by Makita Authorized Service Centers, always
using Makita replacement parts.

Nominal diameter of wood

screw (mm)

Recommended size of pilot

hole (mm)

3.1

2.0 - 2.2

3.5 2.2

2.5

3.8

2.5 - 2.8

4.5

2.9 - 3.2