DeWalt D25899 Instruction Manual page 2

COMPONENTS (Fig. 1)
WARNING: Never modify the power tool or any part of it. Damage or personal injury could
result.
A. On/off switch
B. Rear handle
C. Electronic impact energy control dial (D25901 only)
D. Chisel position index collar
E. Tool holder/sleeve
F. Side handle
INTENDED USE
The D25899, D25901 and D25941 heavy-duty demolition hammers are designed for professional
demolition, chipping and chasing applications in concrete, brick, stone and other masonry
materials. DO NOT use under wet conditions or in presence of flammable liquids or gases.
These heavy-duty demolition hammers are professional power tools. DO NOT let children come
into contact with the tool. Supervision is required when inexperienced operators use this tool.
Residual Risks
• In spite of the application of the relevant safety regulations and the implementation of safety
devices, certain residual risks cannot be avoided.
These are:
– Impairment of hearing.
– Risk of dust inhalation.
– Risk of personal injury due to prolonged use.
– Risk of burns due to accessories becoming hot during operation.
Soft Start Feature
D25901, D25941
The soft start feature allows the impact rate to build up more slowly, thus preventing the chisel
or point from "bouncing" around on the masonry when starting up.
Active Vibration Control
D25901, D25941
The active vibration control neutralizes rebound vibration from the hammer mechanism.
Lowering hand and arm vibration, it allows more comfortable use for longer periods of time and
extends the life of the unit.
Electronic Impact Energy Control Dial
D25901 ONLY (FIG. 1)
The electronic impact energy control dial (C) offers optimal tool control for precise chiselling
with minimal break-out when chiselling soft or brittle materials. It also allows the use of smaller
accessories without risk of breakage.
ASSEMBLY AND ADJUSTMENT
WARNING: Prior to assembly and adjustment always unplug the tool.
WARNING: Always wear gloves when changing accessories. The exposed metal parts on the
tool and accessory may become extremely hot during operation.
WARNING: Since accessories, other than those offered by D
with this product, use of such accessories with this tool could be hazardous. To reduce the risk
of injury, only D WALT, recommended accessories should be used with this product.
E
CAUTION: To reduce dust contamination in the tool, keep dust and debris away from the bit and
the beat piece.
Inserting and Removing SDS-max® Accessories
CAUTION: To reduce the risk of tool damage, only use SDS max shank accessories with the
D25899 and the D25901.
D25901 D25899 (FIG. 2, 3)
This machine uses SDS-max® chisels (refer to the inset in Figure 3 for a cross-section of a
chisel shank).
1. Clean and grease the chisel shank.
CAUTION: Do not apply lubricant to the machine.
2. Insert the chisel shank into the tool holder/sleeve (E). Press and turn the chisel slightly until
the sleeve snaps into position.
3. Pull on the chisel to check if it is properly locked. The hammering function requires the chisel
to be able to move axially several centimeters when locked in the tool holder.
4. To remove a chisel, pull back the tool holder/sleeve (E) and pull the chisel out of the tool
holder.
Inserting and Removing 19 mm Hex Accessories
CAUTION: To reduce the risk of tool damage, only use 3/4" (19 mm) hex shank accessories
with the D25941.
D25941 (FIG. 4, 5)
This machine uses chisels with a 19 mm hex shank (refer to the inset in Figure 5 for a
cross-section of a chisel shank).
1. Clean and grease the chisel shank.
CAUTION: Do not apply lubricant to the machine.
2. Pull back the tool holder/sleeve (E), align the groove (G) with the yellow marker (H) and insert
the chisel shank into the tool holder. Release the locking sleeve.
3. Pull on the chisel to check if it is properly locked. The hammering function requires the chisel
to be able to move axially several centimetres when locked in the tool holder.
4. To remove a chisel, pull back the tool holder/sleeve (E) and pull the chisel out of the tool
holder.
Indexing the Chisel Position (Fig. 6)
The chisel can be indexed and locked into 12 different positions.
1. Insert the chisel as described above.
2. Rotate the chisel position collar (D) in the direction of the arrow until the chisel is in the
desired position.
Setting the Electronic Impact Energy Control Dial
D25901 (FIG. 1)
Turn the dial (C) to the desired level. The higher the number, the greater the impact energy. With
dial settings from 1 (low) to 7 (full power) the tool is extremely versatile and adaptable for many
different applications.
The required setting is a matter of experience, for example:
• when chiselling soft, brittle materials or when minimum break-out is required, set the dial to
1 or 2 (low);
• when breaking harder materials, set the dial to 7 (full power).
Fitting and Adjusting the Side Handle (Fig. 7)
The side handle (F) can be mounted on the front of the machine to suit both right- and left-hand
users.
WARNING: Always operate the machine with the side handle properly mounted.
1. Unscrew the side handle clamp knob (G).
2. Slide the side handle assembly onto the machine locating the steel ring (I) in the mounting
area (X). The correct position of the side handle is between head and middle of the tube.
3. Adjust the side handle (F) to the desired angle.
4. Slide and rotate the side handle to the desired position.
5. Lock the side handle in place by tightening the clamp knob (J).
Instructions for Use
WARNING: Always observe the safety instructions and applicable regulations.
WARNING: Be aware of the location of pipework and wiring.
WARNING: Apply a pressure of approx. 44–66 lbs. (20–30 kg.) to the tool. Excessive force
does not speed up chiselling but decreases tool performance and may shorten tool life.
Switching On and Off (Fig. 1)
To turn the tool on, set the on/off switch (A) to position 1. To turn the tool off, set the on/off switch
(A) to position 0.
Demolition, Chasing and Channelling (Fig. 1)
WARNING: Ensure that the cutting edge does not show discoloration caused by too much
pressure. This may impair the hardness of the accessory.
FIG. 1
FIG. 2
WALT, have not been tested
E
FIG. 4
FIG. 6
Various types of chisels are available as an option.
1. Select the appropriate chisel. Clean and grease its shank.
2. Insert the chisel and check whether it is properly locked.
3. Set the desired impact energy level.
4. Fit and adjust the side handle (F) and make sure it is firmly tightened.
5. Hold the tool at both handles (B, F) and switch on. The tool now runs in continuous
operation.
6. Always switch off the tool when work is finished and before unplugging.
MAINTENANCE
WARNING: To reduce the risk of serious personal injury, turn tool off and disconnect
tool from power source before making any adjustments or removing/installing attachments
or accessories.
Lubrication
Your power tool requires no additional lubrication.
Cleaning
WARNING: Blow dirt and dust out of all air vents with dry air at least once a week.
Wear proper ANSI Z87.1 (CAN/CSA Z94.3) eye protection and proper NIOSH/OSHA/MSHA
respiratory protection when performing this.
WARNING: Never use solvents or other harsh chemicals for cleaning the non-metallic parts of
the tool. These chemicals may weaken the materials used in these parts. Use a cloth dampened
only with water and mild soap. Never let any liquid get inside the tool; never immerse any part
of the tool into a liquid.
Repairs
This machine is not user-serviceable. Take the tool to an authorized D
after approximately 100 hours of use. If problems occur before this time contact an authorized
D WALT repair agent.
E
E
D
D25899
D25901
E
D
D25941
E
D
F
D25899
D25901
D25941
D
C
FIG. 3
D25899
D25901
E
FIG. 5
D25941
H
19 mm
E
G
FIG. 7
F
I
J
WALT repair agent
E
A
B
A
B
A
B