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DEWALT DCF921 20V Max Compact Impact Wrench Manual

DEWALT DCF921 20V Max Compact Impact Wrench Manual Image

Instruction Manual

DCF921, DCF922, DCF923
20V Max* Compact Impact Wrench

If you have questions or comments, contact us.


  1. Trigger switch
  2. Forward/reverse button
  3. Anvil
  4.  Battery release button
  5. Battery pack
  6. Worklight
  7. Mode selector
  8. Belt hook
  9. Screw
  10. Main handle
  11. Worklight switch

Fig. B

75–100% charged

DEWALT DCF921 20V Max Compact Impact Wrench - charged 1
51–74% charged

< 50% charged

Pack needs to be charged

Fig. C


Fully Charged

Hot/Cold Pack Delay

WarningWARNING: Read all safety warnings and all instructions. Failure to follow the warnings and instructions may result in electric shock, fire and/or serious injury.
Danger icon WARNING: To reduce the risk of injury, read the instruction manual.

Intended Use

This impact wrench is designed for professional impact fastening and drilling applications. The impact function makes this tool particularly useful for driving fasteners in wood, metal and concrete.
DO nOT use under wet conditions or in presence of flammable liquids or gases.
DO nOT let children come into contact with the tool. Supervision is required when inexperienced operators use this tool.

Definitions: Safety Alert Symbols and Words
This instruction manual uses the following safety alert symbols and words to alert you to hazardous situations and your risk of personal injury or property damage.
Warning DANGER: Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury.
Warning WARNING: Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
Warning CAUTION: Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.
Warning(Used without word) Indicates a safety related message.
 NOTICE: Indicates a practice not related to personal injury which, if not avoided, may result in property damage.
Warning WARNING : Read all safety warnings, instructions, illustrations and specifications provided with this power tool. Failure to follow all instructions listed below may result in electric shock, fire and/or serious injury.

The term “power tool” in the warnings refers to your mains‑operated (corded) power tool or battery‑operated (cordless) power tool.

  1. Work Area Safety
    a ) Keep work area clean and well lit. Cluttered or dark areas invite accidents.
    b ) Do not operate power tools in explosive atmospheres, such as in the presence of flammable liquids, gases or dust. Power tools create sparks which may ignite the dust or fumes.
    c ) Keep children and bystanders away while  operating a power tool. Distractions can cause you to lose control.
  2. Electrical Safety
    a ) Power tool plugs must match the outlet. Never modify the plug in any way. Do not use any adapter plugs with earthed (grounded) power tools. Unmodified plugs and matching outlets will reduce risk of electric shock.
    b ) Avoid body contact with earthed or grounded  surfaces, such as pipes, radiators, ranges and refrigerators. There is an increased risk of electric shock if your body is earthed or grounded.
    c ) Do not expose power tools to rain or wet conditions. Water entering a power tool will increase the risk of electric shock.
    d ) Do not abuse the cord. Never use the cord for carrying, pulling or unplugging the power tool.  Keep cord away from heat, oil, sharp edges ormoving parts. Damaged or  entangled cords increase the risk of electric shock.
    e ) When operating a power tool outdoors, use an extension cord suitable for outdoor use. Use of  a cord suitable for outdoor use reduces the risk of electric shock.
    f ) If operating a power tool in a damp location is unavoidable, use a ground fault circuit  interrupter (GFCI) protected supply. Use of a GFCIreduces the risk of electric  hock.
  3. Personal Safety
    a ) Stay alert, watch what you are doing and use common sense when operating a power tool. Do not use a power tool while you are tired or under the influence of drugs, alcohol or medication. A moment of inattention while operating power tools may result in serious personal injury.
    b ) Use personal protective equipment. Always wear eye protection. Protective equipment such as a dust mask, non‑skid safety shoes, hard hat, or hearing protection used for appropriate conditions will reduce personal injuries.
    c ) Prevent unintentional starting. Ensure the switch is in the off‑position before connecting to power source and/or battery pack, picking up or carrying the tool. Carrying power tools with your finger on the  switch or energizing power tools that have the switch on invites accidents.
    d ) Remove any adjusting key or wrench before turning the power tool on. A wrench or a key left attached to a rotating part of the power tool may result in personal injury.
    e ) Do not overreach. Keep proper footing and balance at all times. This enables better control of the power tool in unexpected situations.
    f ) Dress properly. Do not wear loose clothing or jewelry. Keep your hair, clothing and gloves away from moving parts. Loose clothes, jewelry or long hair can be caught in moving parts.
    g ) If devices are provided for the connection of dust extraction and collection facilities, ensure these are connected and properly used. Use of dust collection can reduce dust‑related hazards.
    h ) Do not let familiarity gained from frequent use of tools allow you to become complacent and ignore tool safety principles. A careless action can cause severe injury within a fraction of a second.
  4. Power Tool Use and Care
    a ) Do not force the power tool. Use the correct power tool for your application. The correct power tool will do the job better and safer at the rate for which it was designed.
    b ) Do not use the power tool if the switch does not turn it on and off. Any power tool that cannot be controlled with the switch is dangerous and must be repaired.
    c ) Disconnect the plug from the power source and/ or remove the battery pack, if detachable, from the power tool before making any adjustments, changing accessories, or storing power tools. Such preventive safety measures reduce the risk of starting the power tool accidentally.
    d ) Store idle power tools out of the reach of children and do not allow persons unfamiliar with the power tool or these instructions to operate the power tool. Power tools are dangerous in the hands of untrained users.
    e ) Maintain power tools and accessories. Check for misalignment or binding of moving parts, breakage of parts and any other condition that may affect the power tool’s operation. If damaged, have the power tool repaired before use. Many accidents are caused by poorly maintained power tools.
    f ) Keep cutting tools sharp and clean. Properly maintained cutting tools with sharp cutting edges are less likely to bind and are easier to control.
    g ) Use the power tool, accessories and tool bits etc. in accordance with these instructions, taking into account the working conditions and the work to be performed. Use of the power tool for operations different from those intended could result in a hazardous situation.
    h ) Keep handles and grasping surfaces dry, clean and free from oil and grease. Slippery handles and grasping surfaces do not allow for safe handling and control of the tool in unexpected situations.
  5.  Battery Tool Use and Care
    a ) Recharge only with the charger specified by the manufacturer. A charger that is suitable for one type of battery pack may create a risk of fire when used with another battery pack.
    b ) Use power tools only with specifically designated battery packs. Use of any other battery packs may create a risk of injury and fire.
    c ) When battery pack is not in use, keep it away from other metal objects, like paper clips, coins, keys, nails, screws or other small metal objects,that can make a connection from one terminal to another. Shorting the battery terminals together may cause burns or a fire.
    d ) Under abusive conditions, liquid may be ejected from the battery; avoid contact. If contact accidentally occurs, flush with water. If liquid contacts eyes, additionally seek medical help. Liquid ejected from the battery may cause irritation or burns.
    e ) Do not use a battery pack or tool that is damaged or modified. Damaged or modified batteries may exhibit unpredictable behavior resulting in fire, explosion or risk of injury.
    f ) Do not expose a battery pack or tool to fire or excessive temperature. Exposure to fire or temperature above 265 °F (130 °C) may cause explosion.
    g ) Follow all charging instructions and do not charge the battery pack or tool outside the temperature range specified in the instructions. Charging improperly or at temperatures outside the specified range may damage the battery and increase the risk of fire.
  6.  Service
    a ) Have your power tool serviced by a qualified repair person using only identical replacement parts. This will ensure that the safety of the power tool is maintained.
    b ) Never service damaged battery packs. Service of battery packs should only be performed by the manufacturer or authorized service providers.
    Impact Wrench Safety Warnings – All Operations
    • Hold the power tool by insulated gripping surfaces, when performing an operation where the fastener may contact hidden wiring. Fasteners contacting a “live” wire may make exposed metal parts of the power tool “live” and could give the operator an electric shock.
    • Wear ear protectors during use. Exposure to noise can cause hearing loss.
    Warning WARNING: Impact wrenches are not torque wrenches. DO NOT use this tool for tightening fasteners to specified torques. An independent, calibrated torque  easurement device such as a  torque wrench should be used when under tightenedor over tightened fasteners can lead to the failure of the joint.
    • Wear safety goggles or other eye protection. Hammering and drilling operations cause chips to fly. Flying particles can cause permanent eye damage.
    • Do not operate this tool for long periods of time. Vibration caused by tool action may be harmful to your hands and arms. Use gloves to provide extra cushion and limit exposure by taking frequent rest periods.
    • Accessories and tools get hot during operation. Wear gloves when touching them.

Additional Safety Information

Warning WARNING: Never modify the power tool or any part of it. Damage or personal injury could result.
Warning WARNING: ALWAYS use safety glasses. Everyday eyeglasses are NOT safety glasses. Also use face or dust mask if cutting operation is dusty. ALWAYS WEAR

  • ANSI Z87.1 eye protection (CAN/CSA Z94.3),
  • ANSI S12.6 (S3.19) hearing protection,
  • NIOSH/OSHA/MSHA respiratory protection.
    Warning WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the State of California to cause cancer, birth defects or other reproductive harm. Some examples of these chemicals are:
  • lead from lead‑based paints,
  • crystalline silica from bricks and cement and other masonry products, and
  • arsenic and chromium from chemically‑treated lumber.
    Your risk from these exposures varies, depending on how often you do this type of work. To reduce your exposure to these chemicals: work in a well ventilated area, and work with approved safety equipment, such as those dust masks that are specially designed to filter out microscopic particles.
  • Wear protective clothing and wash exposed areas with soap and water. Allowing dust to get into your mouth, eyes, or lay on the skin may promote absorption of  armful  hemicals. Direct particles away from face and body.
  • Use the appropriate dust extractor vacuum to remove the vast majority of static and airborne dust. Failure to remove static and airborne dust could contaminate the working environment or pose an increased health risk to the operator and those in close proximity.
  • Use clamps or other practical ways to secure and support the workpiece to a stable platform. Holding the work by hand or against your body is unstable and may lead to loss of control and injury.
  • Air vents often cover moving parts and should be avoided. Loose clothes, jewelry or long hair can be caught in moving parts.
    CAUTION: When not in use, place tool on its side on a stable surface where it will not cause a tripping or falling hazard. Some tools with large battery packs will stand upright on the battery pack but may be easily knocked over. The label on your tool may include the following symbols. The symbols and their definitions are as follows:

V ……………………. volts
Hz ………………….. hertz
min ………………… minutes
or DC …… direct current
…………………. Class I Construction (grounded)
…/min ………….. per minute

BPM ……………….. beats per minute
IPM ………………… impacts per minute
OPM ……………….. oscillations per minute
RPM ……………….. revolutions per minute

sfpm ………………. surface feet per minute
SPM ……………….. strokes per minute
A ……………………. amperes
W …………………… watts
Wh …………………. watt hours
Ah ………………….. amp hours
 ……….. alternating current
…. alternating or direct current
Double insulation…………………. Class II Construction (double insulated)
no ………………….. no load speed
n ……………………. rated speed
PSI………………….. pounds per square inch
…………………. earthing terminal
Warning………………… safety alert symbol
………………… visible radiation
………………… wear respiratory protection
………………… wear eye protection
………………… wear hearing protection
.Danger icon……………….. read all documentation

The battery pack is not fully charged out of the carton.
Before using the battery pack and charger, read the safety instructions below and then follow charging procedures outlined. When ordering replacement battery packs, be sure to include the catalog number and voltage.

Important Safety Instructions for All Battery Packs
Warning WARNING: Read all safety warnings, instructions, and cautionary markings for the battery pack, charger and product. Failure to follow the warnings and instructions may result in electric shock, fire and/or serious injury.

  •  Do not charge or use the battery pack in explosive atmospheres, such as in the presence of flammable liquids, gases or dust. Inserting or removing the battery pack from the charger may ignite the dust or fumes.
  • NEVER force the battery pack into the charger. DO NOT modify the battery pack in any way to fit into a non‑compatible charger as battery pack may rupture causing serious personal injury. Consult the chart at the end of this manual for compatibility of batteries and chargers.
  • Charge the battery packs only in DeWALT chargers.
  • DO NOT splash or immerse in water or other liquids.
  • DO NOT allow water or any liquid to enter battery pack.
  • Do not store or use the tool and battery pack in locations where the temperature may reach or exceed 104 °F (40 °C) (such as outside sheds or metal buildings in summer). For best life store battery packs in a cool, dry location.
    NOTE: Do not store the battery packs in a tool with the trigger switch locked on. Never tape the trigger switch in the ON position.
  • Do not incinerate the battery pack even if it is severely damaged or is completely worn out. The battery pack can explode in a fire. Toxic fumes and materials are created when lithium‑ion battery packs are burned.
  • Do not expose a battery pack or appliance to fire or excessive temperature. Exposure to fire or temperature above 265 °F (130 °C) may cause explosion.
  • If battery contents come into contact with the skin, immediately wash area with mild soap and water. If battery liquid gets into the eye, rinse water over the open eye for 15 minutes or until irritation ceases. If medical attention is needed, the battery electrolyte is composed of a mixture of liquid organic carbonates and lithium salts.
  • Contents of opened battery cells may cause respiratory irritation. Provide fresh air. If symptoms persist, seek medical attention.
  • Battery liquid may be flammable if exposed to spark or flame.
  • Never attempt to open the battery pack for any reason. If the battery pack case is cracked or damaged, do not insert into the charger. Do not crush, drop or damage the battery pack. Do not use a battery pack or charger that has received a sharp blow, been dropped, run over or damaged in any way (e.g., pierced with a nail, hit with a hammer, stepped on). Damaged battery packs should be returned to the service center for recycling.

Storage Recommendations
The best storage place is one that is cool and dry, away from direct sunlight and excess heat or cold. Store the fully charged battery pack out of the charger.
Battery Pack Cleaning Instructions
Dirt and grease may be removed from the exterior of the battery pack using a cloth or soft non‑metallic brush. Do not use water or any cleaning solutions.
Fuel Gauge Battery Packs (Fig. B)
Some battery packs include a fuel gauge. When the fuel gauge button is pressed and held, the LED lights will indicate the approximate level of charge remaining. This does not indicate tool functionality and is subject to variation based on product components, temperature, and end‑user application.

Warning WARNING: Fire hazard. Do not store, carry, or transport the battery pack so that metal objects can contact exposed battery terminals. For example, do not place the battery pack in aprons, pockets, tool boxes, product kit boxes, drawers, etc., with loose nails, screws, keys, coins, hand tools, etc. When transporting individual battery packs, make sure that the battery terminals are protected and well insulated from materials that could contact them and cause a short circuit. NOTE: Li‑ion battery packs should not be put in checked baggage on airplanes and must be properly protected from short circuits if they are in carry‑on baggage. shipping the DeWALT FlEXVOlT™ Battery Pack
The DeWALT FLEXVOLT™ battery pack has a battery cap that should be used when shipping the battery pack.

DEWALT DCF921 20V Max Compact Impact Wrench - battery

Attach the cap to the battery pack to ready it for shipping.
This converts the battery pack to three separate 20V batteries. The three batteries have the Watt hour rating labeled “Shipping” on the battery pack. If shipping without
the cap or in a tool, the pack is one battery at the Watt hour rating labeled “Use”.

Example battery pack label:

USE: 120 Wh SHIPPING: 3 x 40 Wh 
In this example, the battery pack is three batteries with 40 Watt hours each when using the cap. Otherwise, the battery pack is one battery with 120 Watt hours.

DEWALT DCF921 20V Max Compact Impact Wrench - Seal

The RBRC® Seal
Please take your spent battery packs to an authorized DeWALT service center or to your local retailer for recycling. In some areas, it is illegal to place spent battery
packs in the trash. You may also contact your local recycling center for information on where to drop off the spent battery pack. Do not place in curbside recycling. For more
information visit www.call2recycle.org. or call the toll free number in the RBRC® Seal. RBRC® is a registered trademark of Call 2 Recycle, Inc.

Important Safety Instructions for All Battery Chargers

WARNING: Read all safety warnings, instructions, and cautionary markings for the battery pack, charger and product. Failure to follow the warnings and instructions may result in electric shock, fire and/or serious injury.

  • DO NOT attempt to charge the battery pack with any chargers other than a DeWALT charger. DeWALT chargers and battery packs are specifically designed to work together.
  • These chargers are not intended for any uses other than charging DeWALT rechargeable battery packs. Charging other types of battery packs may cause them to overheat and burst, resulting in personal injury, property damage, fire, electric shock or electrocution.
  • Do not expose the charger to rain or snow.
  • Do not allow water or any liquid to enter charger.
  • Pull by the plug rather than the cord when disconnecting the charger. This will reduce the risk of damage to the electric plug and cord.
  • Make sure that the cord is located so that it will not be stepped on, tripped over or otherwise subjected to damage or stress.
  • Do not use an extension cord unless it is absolutely necessary. Use of improper extension cord could result in risk of fire, electric shock or electrocution.
  • When operating a charger outdoors, always provide a dry location and use an extension cord suitable for outdoor use. Use of a cord suitable for outdoor use reduces the risk of electric shock.
  • An extension cord must have adequate wire size (AWG or American Wire Gauge) for safety. The smaller the gauge number of the wire, the heavier the cord and thus the greater its capacity. An undersized cord will cause a drop in line voltage resulting in loss of power and overheating. The following table shows the correct size to use depending on total length of all extension cords plugged together, and nameplate ampere rating. If in doubt, use the next heavier gauge.

Minimum gauge for Cord sets

Volts Total length of Cord in Feet(meters)
120V 25 (7.6) 50 (15.2) 100 (30.5) 150 (45.7)
Ampere Rating American Wire gauge
More Than Not MoreThan
0 6 18 16 16 14
6 10 18 16 14 12
10 12 16 16 14 12
12 16 14 12 Not Recommended
  • Do not place any object on top of the charger or place the charger on a soft surface that might block the ventilation slots and result in excessive internal heat. Place the charger in a position away from any heat source. The charger is ventilated through slots in the top and the bottom of the housing.
  • Do not operate the charger with a damaged cord or plug. Have them replaced immediately.
  • Do not operate the charger if it has received a sharp blow, been dropped or otherwise damaged in any way. Take it to an authorized service center.
  • Do not disassemble the charger; take it to an authorized service center when service or repair is required. Incorrect reassembly may result in a risk of electric shock, electrocution or fire.
  • The charger is designed to operate on standard 120V household electrical power. Do not attempt to use it on any other voltage. This does not apply to the vehicular charger.
  • Foreign materials of a conductive nature, such as, but not limited to, grinding dust, metal chips, steel wool, aluminum foil or any buildup of metallic particles should be kept away from the charger cavities and ventilation slots.
  • Always unplug the charger from the power supply when there is no battery pack in the cavity.

Charging a Battery (Fig. C)

  1.  Plug the charger into an appropriate outlet.
  2.  Insert and fully seat battery pack. The red charging light(s) will continuously blink while charging.
  3. Charging is complete when the red charging light(s) remain(s) continuously ON. Battery pack can be left in charger or removed. Some chargers require the battery pack release button to be pressed for removal.
    Warning WARNING: Only charge batteries in air temperature over 40 ° F (4.5 ° C)  and below 104 ° F (+40 ° C).
  4. Charger will not charge a faulty battery pack, which may be indicated by the charging light(s) staying OFF. Take charger and battery pack to an authorized service center
    if light(s) stay(s) OFF.
    nOTE: Refer to label near charging light(s) on charger for blink patterns. Older chargers may have additional information and/or may not have a yellow indicator light.
    nOTE: To remove the battery pack, some chargers require the battery pack release button to be pressed.

hot/Cold Pack Delay
When the charger detects a battery pack that is too hot or too cold, it automatically starts a Hot/Cold Pack Delay, suspending charging until the battery pack has reached an
appropriate temperature. The charger then automatically switches to the pack charging mode. This feature ensures maximum battery pack life.
A cold battery pack may charge at a slower rate than a warm battery pack.
The hot/cold pack delay will be indicated by the red light(s) continuing to blink but with the yellow light continuously ON. Once the battery pack has reached an appropriate
temperature, the yellow light will turn OFF and the charger will resume the charging procedure.

DCB118 and DCB1112 Chargers
The DCB118 and DCB1112 chargers are equipped with an internal fan designed to cool the battery pack. The fan will turn on automatically when the battery pack needs to
be cooled.
Never operate the charger if the fan does not operate properly or if ventilation slots are blocked. Do not permit foreign objects to enter the interior of the charger.

Electronic Protection System
Li‑Ion tools are designed with an Electronic Protection System that will protect the battery pack against overloading, overheating or deep discharge. The tool will automatically
turn off and the battery pack will need to be recharged.

Important Charging Notes

  1. Longest life and best performance can be obtained if the battery pack is charged when the air temperature is between 65 °F – 75 °F (18 ° C– 24 °C). DO NOT charge
    when the battery pack is below +40 °F (+4.5 °C), or above +104 °F (+40 °C). This is important and will prevent serious damage to the battery pack.
  2. The charger and battery pack may become warm to the touch while charging. This is a normal condition, and does not indicate a problem. To facilitate the cooling of the battery pack after use, avoid placing the charger or battery pack in a warm environment such as in a metal shed or an uninsulated trailer.
  3. If the battery pack does not charge properly:a. Check operation of receptacle by plugging in a lamp or other appliance;
    b. Check to see if receptacle is connected to a light switch which turns power off when you turn out the lights;
    c. If charging problems persist, take the tool, battery pack and charger to your local service center.
  4. You may charge a partially used pack whenever you desire with no adverse effect on the battery pack.

Charger Cleaning Instructions

WARNING: Shock hazard. Disconnect the charger from the AC outlet before cleaning. Dirt and grease may be removed from the exterior of the charger using a cloth or soft non‑metallic brush. Do not use water or any cleaning solutions.

Wall Mounting

Some DeWALT chargers are designed to be wall mountable or to sit upright on a table or work surface.  If wall mounting, locate the charger within reach of an electrical outlet, and away from a corner or other obstructions which may impede air flow. Use the back of the charger as a template for the location of the mounting screws on the wall. Mount the charger securely using drywall screws (purchased separately) at least 1” (25.4 mm) long, with a screw head diameter of 0.28–0.35” (7–9 mm), screwed into wood to an optimal depth leaving approximately 7/32” (5.5 mm) of the screw exposed. Align the slots on the back of the charger with the exposed screws and fully engage them in the slots.

Warning  WARNING: To reduce the risk of serious personal injury, turn unit off and remove the battery packbefore making any adjustments or removing/ installing attachments or accessories. An accidental start‑up can cause injury.

Anvil (Fig. E)
Warning WARNING: Use only impact accessories. Non‑impact accessories may break and cause a hazardous condition. Inspect accessory prior to use to ensure that it contains no cracks.
Warning CAUTION: Inspect anvils, detent pins, and hog rings prior to use. Missing or damaged items should be replaced before use.
Place the switch in the locked off (center) position or remove battery pack before changing accessories.

Anvil with Detent Pin (Fig. E) DCF922
To install an accessory on the anvil, align the hole in the side of the accessory with the detent pin  13  on the anvil  3 . Press the accessory on until the detent pin engages in the hole. Depression of detent pin may be necessary to aid installation of accessory.To remove an accessory, depress the detent pin through the hole and pull the accessory off.
Anvil With Hog Ring (Fig. E) DCF921, DCF923 To install an accessory on the hog ring anvil, firmly push accessory onto the anvil  3 . The hog ring  12  compresses to allow the accessory to slide on. After accessory is installed, the hog ring applies pressure to help provide accessory retention. To remove an accessory, grasp the accessory and firmly pull it off.

Belt Hook (Fig. A)
Included with Some Models 
Warning WARNING: To reduce the risk of serious personal injury, ONLY use the tool’s belt hook to hang the tool from a work belt. DO NOT use the belt hook for tethering or securing the tool to a person or object during use. DO NOT suspend tool overhead or suspend objects from the belt hook.
Warning WARNING: To reduce the risk of serious personal injury, ensure the screw holding the belt hook is secure.

iMPORTAnT: When attaching or replacing a belt hook, use only the screw that is provided. Be sure to securely tighten the screw.
A belt hook  8  can be be attached to either side of the tool using only the screw  9  provided, to accommodate left‑ or right‑handed users. If the belt hook is not desired at all, it can be removed from the tool.
To move the belt hook, remove the screw  9  that holds it in place then reassemble on the opposite side. Be sure to securely tighten the screw.

Mode Selector (Fig. A, D)
Your tool is equipped with a mode selector  7  which allows you to select one of two speeds, Timber Screw™ mode, or Precision Wrench™ mode. Select the mode based on the
maximum speed/torque needed and control the speed of the tool using the variable speed trigger switch  1 .

DEWALT DCF921 20V Max Compact Impact Wrench - Screw Timber Screw™ Mode (Fig. D)
Timber Screw™ mode optimizes tool performance to help increase the speed of wood driving applications such as with lag bolts, lag screws and structural wood screws.
DEWALT DCF921 20V Max Compact Impact Wrench - Screw Precision Wrench™ Mode (Fig. D)
In addition to normal impacting modes, this tool features the Precision Wrench™ mode which grants the user greater control in both fastening and loosening applications.
When set in forward, the tool will fasten at 2500 RPM until impact begins. The tool will then pause for 0.5 seconds before continuing to impact at a rate of 3550 IPM, providing the user with greater control and reducing the chance of overtightening or damaging material. When set in reverse, the tool will impact at a normal speed and rate of 3550 IPM. Upon sensing that the fastener has broken free, the tool will cease to impact and will reduce speed to help prevent “run‑off” of loose hardware.


Mode Application RPM
Precision Wrench™ Precision Wrench™ 0‑2500 forward
0‑2500 reverse
Timber Screw™ Timber Screw™ 0‑2500 forward
0‑2500 reverse
Speed 1 Low Speed Impacting 0‑1400 forward
0‑2500 reverse
Speed 2 High Speed Impacting 0‑2500 forward
0‑2500 reverse


WARNING: To reduce the risk of serious personal injury, turn unit off and remove the battery pack before making any adjustments or removing/ installing attachments or accessories. An accidental start‑up can cause injury.

Installing and Removing the Battery Pack (Fig. F)
nOTE: For best results, make sure your battery pack is fully charged.
To install the battery pack  5  into the tool handle, align the battery pack with the rails inside the tool’s handle and slide it into the handle until the battery pack is firmly seated in the tool and ensure that it does not disengage. To remove the battery pack from the tool, press the release button  4  and firmly pull the battery pack out of the tool handle. Insert it into the charger as described in the charger section of this manual.

Proper Hand Position (Fig. G)
Warning WARNING : To reduce the risk of serious personal injury, ALWAYS use proper hand position as shown.
Warning WARNING: To reduce the risk of serious personal injury, ALWAYS hold securely in anticipation of a sudden reaction.
Proper hand position requires one hand on the main handle  10 .

Variable Speed Trigger Switch (Fig. A)
To turn the tool on, squeeze the trigger switch  1 . To turn the tool off, release the trigger switch. Your tool is equipped with a brake. The anvil will stop when the trigger switch is fully released. The variable speed switch enables you to select the best speed for a particular application. The more you squeeze the trigger, the faster the tool will operate. For maximum tool life, use variable speed only for starting holes or fasteners. nOTE: Continuous use in variable speed range is not recommended. It may damage the switch and should be avoided.
Forward/Reverse Control Button (Fig. A)
A forward/reverse control button  2  determines the direction of the tool and also serves as a lock‑off button.

To select forward rotation, release the trigger switch and depress the forward/reverse control button on the right side of the tool.
To select reverse, release the trigger switch and depress the forward/reverse control button on the left side of the tool. The center position of the control button locks the tool in the off position. When changing the position of the control button, be sure the trigger is released.
NOTE: The first time the tool is run after changing the direction of rotation, you may hear a click on start up. This is normal and does not indicate a problem.

Worklight (Fig. A, D)
The worklight  6  is activated when the variable speed trigger  1  is depressed. Pressing the worklight switch  11  repeatedly will cycle through low illumination, high illumination, and off. NOTE: The worklight is for lighting the immediate work surface and is not intended to be used as a flashlight.
Usage (Fig. A)

Warning CAUTION: Ensure fastener and/or system will withstand the level of torque generated by the tool. Excessive torque may cause breakage and possible personal injury.

  1. Place the accessory on the fastener head. Keep the tool pointed straight at the fastener.
  2. Press variable speed trigger switch  1  to start operation. Release variable speed trigger switch to stop operation. Always check torque with a torque wrench, as the fastening torque is affected by many factors including the following:
    ‑ Voltage: Low voltage, due to a nearly discharged battery, will reduce fastening torque.
    ‑ Accessory size: Failure to use the correct accessory size will cause a reduction in fastening torque.
    ‑ Bolt size: Larger bolt diameters generally require higher fastening torque. Fastening torque will also vary according to length, grade, and torque coefficient.
    ‑ Bolt: Ensure that all threads are free of rust and other debris to allow proper fastening torque.
    ‑ Material: The type of material and surface finish of the material will affect fastening torque.
    ‑ Fastening time: Longer fasten ing time results in increased fastening torque. Using a longer fastening time than recommended could cause the fasteners to be overstressed, stripped or damaged.


Max. fastening torque 300 ft‑lbs, 406 Nm
(Speed 2, Timber Screw™,
Precision Wrench™)
150 ft‑lbs, 203 Nm (Speed 1)
Max. breakaway torque 450 ft‑lbs, 610 Nm (all modes)
No load speed 0‑2500 rpm
Impacts per minute 0‑3550 ipm
Length 4.95″ (126 mm)
Weight 2.47 lbs (1.1 kg)


WARNING: To reduce the risk of serious personal injury, turn unit off and remove the battery pack before making any adjustments or removing/ installing attachments or accessories. An accidental start‑up can cause injury.
Your DeWALT power tool has been designed to operate over a long period of time with a minimum of maintenance. Continuous satisfactory operation depends upon proper tool care and regular cleaning.

Warning WARNING: Blow dirt and dust out of all air vents with clean, dry air at least once a week. To minimize the risk of eye injury, always wear ANSI Z87.1 approved eye protection when performing this procedure.
Warning WARNING: Never use solvents or other harsh chemicals for cleaning the non‑metallic parts of the tool. These chemicals may weaken the plastic 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.

Warning WARNING: Since accessories, other than those offered by DeWALT, have not been tested with this product, use of such accessories with this tool could be hazardous. To reduce the risk of injury, only DeWALT recommended accessories should be used with this product.
Recommended accessories for use with your tool are available at extra cost from your local dealer or authorized service center. If you need assistance in locating any accessory, please contact DeWALT call 1‑800‑4‑DeWALT (1‑800‑433‑9258) or visit our website:www.dewalt.com.
Impact Accessories
WarningWARNING: Use only impact accessories. Non‑impact accessories may break and cause a hazardous condition. Inspect accessories prior to use to ensure that they contain no cracks.

The charger and battery pack are not serviceable. There are no serviceable parts inside the charger or battery pack.
Warning WARNING: To assure product SAFETY and RELIABILITY, repairs, maintenance and adjustment (including brush inspection and replacement, when applicable) should be performed by a DeWALT factory service center or a DeWALT authorized service center. Always use identical replacement parts.

Register Online
Thank you for your purchase. Register your product now for:

  • WARRAnTY sERViCE: Registering your product will help you obtain more efficient warranty service in case there is a problem with your product.
  • COnFiRMATiOn OF OWnERshiP: In case of an insurance loss, such as fire, flood or theft, your registration of ownership will serve as your proof of purchase.
  • FOR YOUR sAFETY: Registering your product will allow us to contact you in the unlikely event a safety notification is required under the Federal Consumer Safety Act.
  • Register online at www.dewalt.com

Three Year Limited Warranty
For warranty terms, go to https://www.dewalt.com/Legal/Warranty/3‑Year‑Limited‑Warranty.
To request a written copy of the warranty terms, contact: Customer Service at DeWALT Industrial Tool Co., 701 East Joppa Road, Towson, MD 21286 or call 1‑800‑4‑DeWALT (1‑800‑433‑9258).
lATin AMERiCA: This warranty does not apply to products sold in Latin America. For products sold in Latin America, see country specific warranty information contained in
the packaging, call the local company or see website for warranty information.
FREE WARning lABEl REPlACEMEnT: If your warning labels become illegible or are missing, call 1‑800‑4‑DeWALT (1‑800‑433‑9258) for a free replacement.

Compatible battery packs and chargers

20V Max* li‑ion Battery Packs DCB200, DCB201, DCB203, DCB204, DCB204BT**, DCB205, DCB205BT**, DCB206, DCB208,
DCB210, DCB230, DCB240
Chargers DCB103, DCB104, DCB107, DCB112, DCB113, DCB115, DCB118, DCB132, DCB1106, DCB1112
60V Max* li‑ion Battery Packs DCB606, DCB609, DCB612
Chargers DCB103, DCB104, DCB107, DCB112, DCB113, DCB115, DCB118, DCB132, DCB1106, DCB1112

* Maximum initial battery voltage (measured without a workload) is 20, 60 or 120 volts. Nominal voltage is 18, 54 or 108. (120V Max* is based on using 2 DeWALT 60V Max* lithium‑ion batteries combined.)
**BT ‑ Bluetooth®
NOTE: The Bluetooth® word mark and logos are registered trademarks owned by the Bluetooth®, SIG, Inc. and any use of such marks by DeWALT is under license. Other trademarks and trade names are those of their respective owners.

Warning WARNING: Use of any other battery packs may create a risk of injury and fire.

DeWALT Industrial Tool Co. 701 East Joppa Road, Towson, MD 21286
Copyright © 2021
The following are trademarks for one or more DeWALT power tools: the yellow and black color scheme, the “D” shaped air
intake grill, the array of pyramids on the handgrip, the kit box configuration, and the array of lozenge‑shaped humps on the
surface of the tool.

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