DEWALT DCST922 20V Max* String Trimmer
Instruction Manual
Intended Use
This string trimmer is designed for professional trimming applications. This product is not an edger and is not intended to be used for edging.
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.
IMPORTANT SAFETY INSTRUCTIONS
⚠️ WARNING: To reduce risk of injury:
- Before any use, be sure everyone using this unit reads and understands all safety instructions and other information contained in this manual.
- Save these instructions and review frequently.
⚠️ WARNING: When using electric gardening appliances, basic safety precautions should always be followed to reduce risk of fire, electric shock, and personal injury, including the following:
- 1. Avoid Dangerous Environment – Don't use appliances in damp or wet locations.
- 2. Don't Use In Rain.
- 3. Keep Children Away – All visitors should be kept at a distance from work area.
- 4. Dress Properly – Do not wear loose clothing or jewelry. They can be caught in moving parts. Use of rubber gloves and substantial footwear is recommended when working outdoors. Wear protective hair covering to contain long hair.
- 5. Use Safety Glasses – Always use face or dust mask if operation is dusty.
- 6. Use Right Appliance – Do not use appliance for any job except that for which it is intended.
- 7. Don't grasp the exposed cutting blades or cutting edges when picking up or holding the appliance.
- 8. Don't Force Appliance – It will do the job better and with less likelihood of a risk of injury at the rate for which it was designed.
- 9. Don't Overreach – Keep proper footing and balance at all times.
- 10. Stay Alert – Watch what you are doing. Use common sense. Do not operate appliance when you are tired.
- 11. Disconnect Appliance – Remove the battery when not in use, before servicing, when changing accessories such as blades, and the like.
- 12. Store Idle Appliances Indoors – When not in use, appliances should be stored indoors in dry, and high or locked-up place – out of reach of children.
- 13. Maintain Appliance With Care – Keep cutting edge sharp and clean for best performance and to reduce the risk of injury. Follow instructions for lubricating and changing accessories. Inspect appliance power source periodically, and if damaged, have it repaired by an authorized service facility. Keep handles dry, clean, and free from oil and grease.
- 14. Check Damaged Parts – Before further use of the appliance, a guard or other part that is damaged should be carefully checked to determine that it will operate properly and perform its intended function. Check for alignment of moving parts, binding of moving parts, breakage of parts, mounting, and any other condition that may affect its operation. A guard or other part that is damaged should be properly repaired or replaced by an authorized service center unless indicated elsewhere in this manual.
Additional Safety Warnings
⚠️ WARNING: To reduce the risk of rebound (ricochet) injury, work going away from any nearby solid object such as wall, steps, large stone, tree, etc.
GUARD – Do not use this appliance without guard attached.
DRESS PROPERLY – Do not wear loose clothing or jewelry. They can be caught in moving parts. Gloves and substantial rubber soled footwear are recommended when working outdoors. Don't operate the appliance when barefoot or wearing open sandals. Wear heavy long pants to protect your legs. Wear protective hair covering to contain long hair.
KEEP FACE, HANDS AND FEET CLEAR OF ROTATING NYLON LINE AT ALL TIMES. The rotating line performs a cutting function. Use care when trimming around screens and desirable plantings.
KEEP ALL BYSTANDERS AWAY – at a safe distance from work area, especially children. MAKE SURE that other persons and pets are at least 100' (30 m) away.
USE GREAT CARE when working close to solid objects and where necessary, do trimming by hand.
AVOID ACCIDENTALLY STARTING – Don't carry with finger on trigger when battery is installed.
DAMAGE TO UNIT – If you strike or become entangled with a foreign object, stop appliance immediately, check for damage and have any damage repaired before further operation is attempted. Do not operate with a broken hub or spool.
DO NOT OPERATE portable electric appliances in gaseous or explosive atmospheres. Motors in these appliances normally spark, and the sparks might ignite fumes.
STAY ALERT – Do not operate this unit when you are tired, ill, or under the influence of alcohol, drugs, or medication.
DO NOT immerse appliance in water or squirt it with a hose.
DO NOT allow any liquid to get inside it. If appliance does get wet, allow to dry for a minimum of 48 hours.
DO NOT clean with a pressure washer.
DO NOT store the appliance on or adjacent to fertilizers or chemicals.
DO NOT charge appliance in rain, or in wet locations.
TO REDUCE THE RISK OF INJURY, do not operate the unit while folded. The unit must be fully extended and the pole clasp secured before the battery is inserted.
REMOVE BATTERY BEFORE FOLDING THE UNIT. Fold unit completely until it locks in place.
⚠️ CAUTION: Use only DEWALT replacement spools and line. Using any other manufacturer's line can reduce performance, damage the trimmer or cause personal injury. Your trimmer uses 0.080 inches (2.0 mm) diameter line. Do not use other size lines. This can degrade performance, cause damage to the unit or injury.
⚠️ WARNING: Do not use appliance if the switch trigger does not turn the appliance on or off. Any appliance that cannot be controlled with the switch trigger is dangerous and must be repaired.
Assembly and Adjustments
⚠️ 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.
Extending and Folding the Pole (Fig. A, B, P)
⚠️ WARNING: To reduce the risk of injury, do not operate the unit while folded. The unit must be fully extended and the pole clasp secured before the battery is inserted. Remove battery before folding the unit. Fold unit completely until it locks in place.
1. To lock pole into straight use position, first ensure battery has been removed. Then flip up the locking lever 6 , rotate pole latch 7 forward, and place the pole clasp 8 over the clasp catch 18 . Rotate the pole latch 7 backwards until it locks securely into position. Check the locking lever to make sure it is properly locked in place.
2. To fold the pole for storage or transportation, first ensure battery has been removed. Then flip up the locking lever 6 , rotate pole latch 7 forward and lift the pole clasp 8 up and over the clasp catch 18 . Fold the pole completely until the guard 9 securely locks into place over the rear of the battery housing 11 .
Attaching the Auxiliary Handle (Fig. A, C)
1. Place the auxiliary handle 4 on top of the handle base 20 so the upper trimmer pole 15 is between them.
2. Hold the auxiliary handle in place and slide the handle bolts 21 into the handle from the top, threading them into the handle base.
3. Tighten the handle bolts with the supplied hex wrench. Ensure the handle is securely attached.
Attaching Guard (Fig. D, E)
⚠️ WARNING: Never remove the guard. Damage or personal injury could result.
⚠️ WARNING: NEVER OPERATE APPLIANCE WITHOUT GUARD FIRMLY IN PLACE. The guard must always be properly attached on the appliance to protect the user.
1. Assemble the guard 9 to the motor housing 5 .
2. Using a crosshead screwdriver, insert the 2 guard screws 19 and tighten securely.
NOTE: An extended coverage guard is available (sold separately) for extra coverage if desired. Use replacement guard Part Number N776035 for Type 1 units or N890579 for Type 2, 10, and beyond units.
Operation
⚠️ 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 12 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 13 and firmly pull the battery pack out of the tool handle. Insert it into the charger.
Proper Hand Position (Fig. G)
⚠️ WARNING: To reduce the risk of serious personal injury, ALWAYS use proper hand position as shown.
⚠️ WARNING: To reduce the risk of serious personal injury, ALWAYS hold securely in anticipation of a sudden reaction.
⚠️ WARNING: Always use proper eye protection that conforms to ANSI Z87.1 (CAN/CSA Z94.3) while operating this appliance.
⚠️ WARNING: Remove the battery before making any assembly, adjustments, or changing accessories. Such preventive safety measures reduce the risk of starting the TRIMMER accidentally.
⚠️ CAUTION: Before you begin trimming, only use the appropriate type of cutting line.
⚠️ CAUTION: Inspect area to be trimmed and remove any wire, cord, or string-like objects which could become entangled in the rotating line or spool. Be particularly careful to avoid any wire which might be bent outwardly into the path of the appliance, such as barbs at the base of a chain link fence.
Proper hand position requires one hand on the primary handle 14 and one hand on the auxiliary handle 4 .
Switching Trimmer On and Off (Fig. A)
To turn the appliance on, squeeze the lockoff button 2 and then the variable speed trigger 1 .
To turn the appliance off, release the variable speed trigger and the lockoff button.
⚠️ WARNING: Never attempt to lock the trigger in the on position.
Speed Control Switch (Fig. A)
This string trimmer gives you the choice to operate at a more efficient speed to extend the runtime for larger jobs, or accelerate the trimmer speed for high-performance cutting.
To extend runtime, push the speed control switch 3 forward toward the auxiliary handle 4 into the "LO" position. This mode is best for larger projects that require more time to complete.
To accelerate the trimmer, pull the speed control switch back toward the battery housing 11 into the "HI" position. This mode is best to cut through heavier growth and for applications that need higher RPM.
NOTE: When in "HI" mode, runtime will be decreased as compared to when trimmer is in "LO" mode.
Trimming (Fig. H, I)
With the trimmer on, angle it and swing side to side as shown in Fig. I.
Maintain a minimum distance of 24" (610 mm) between the guard and your feet as shown in Fig. H.
⚠️ WARNING: Keep the rotating string roughly parallel with the ground (tilted no more than 30 degrees). This trimmer is not an edger. DO NOT TILT the trimmer so that the string is spinning near a right angle to the ground. Flying debris can cause serious injury.
Bump Feed Trimmer Line Feed
Your trimmer uses 0.080" (2.0 mm) diameter nylon line. Cutting line will wear faster and require more feeding if the cutting is done along sidewalks or other abrasive surfaces or heavier weeds are being cut.
As you use the trimmer, the string will get shorter due to wear. Gently bump the trimmer on the ground while running at normal speed and the line will feed.
NOTE: Extending nylon line beyond the 14" (355 mm) swath will negatively affect performance, runtime, and the life of the trimmer due to potential of damaging motor. Doing so may void the warranty.
Helpful Cutting Tips
- Use the tip of the string to do the cutting; do not force string head into uncut grass.
- Wire and picket fences cause extra string wear, even breakage. Stone and brick walls, curbs, and wood may wear string rapidly.
- Do not allow spool cap to drag on ground or other surfaces.
- In long growth, cut from the top down and do not exceed 12" (304.8 mm) high.
- Keep trimmer tilted toward the area being cut; this is the best cutting area.
- The trimmer cuts when passing the unit from the left to right. This will avoid throwing debris at the operator.
- Avoid trees and shrubs. Tree bark, wood moldings, siding, and fence posts can easily be damaged by the string.
Maintenance
⚠️ 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.
Maintenance Treatments (Fig. J)
- Keep the air intake slots 26 clean to avoid overheating (Fig. J).
- Your trimmer line can dry out over time. To keep your line in top condition, store spare line in a plastic, sealable bag with a tablespoon of water.
- Plastic parts may be cleaned by using a mild soap and a damp rag.
The line cutter on the edge of the guard can dull over time. It is recommended you periodically touch-up the sharpness of the blade with a file.
Cleaning
⚠️ 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: 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.
Accessories
⚠️ 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.
Replacement Accessories
⚠️ WARNING: To reduce the risk of serious personal injury, turn appliance off and remove battery before making any adjustments or removing/installing attachments or accessories.
⚠️ WARNING: The use of any accessory not recommended by DEWALT for use with this appliance could be hazardous.
⚠️ WARNING: Do not use any blades, or any accessory or attachment other than those recommended by DEWALT on this trimmer. Serious injury or product damage may result.
Use DEWALT replacement line Model No. DWO1DT801 or DWO1DT802.
When replacing the line, use only 0.080" (2.0 mm) diameter line (Model No. DWO1DT801 or DWO1DT802 are recommended). Other sizes may degrade performance or cause damage to the trimmer.
Reloading the Cutting Line (Fig. K-M)
⚠️ 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, when replacing line, or prior to cleaning. An accidental start-up can cause injury.
⚠️ CAUTION: Use only DEWALT replacement spools and line. Using any other manufacturer's line can reduce performance, damage the trimmer or cause personal injury.
Your trimmer uses 0.080" (2.0 mm) diameter line that is spiral-shaped with smooth round edges. Do not use other size lines. This can degrade performance, causing damage to the unit or injury.
⚠️ CAUTION: To avoid appliance damage, if the cutting line protrudes beyond the trimming blade, cut it off so that it just reaches the blade.
Use only DEWALT replacement line.
1. Remove battery.
2. Cut a max of 20' (6 m) length of 0.080" (2.0 mm) trimmer line.
3. Align spool housing eyelets 22 with the arrow 23 on the spool grip cover 25 as shown in Fig. K.
4. Thread one end of the trimmer line through an eyelet. Guide the line through to the second eyelet and continue to pull the line through until there are equal lengths of string on each side of the spool housing as shown in Fig. L.
5. Secure the spool cap from moving with one hand. Using your other hand, wind the string onto the spool by rotating the spool grip cover counterclockwise. Continue winding until 5" (130 mm) of string remain on each side of the spool housing.
Replacing Spool Assembly (Fig. A, N)
1. Rotate the spool housing 10 until the hole 27 in the spindle plate aligns with notch 28 in the motor housing. Insert a screwdriver through the notch and into the hole, to prevent the spindle from turning.
2. Unscrew and remove the spool housing by turning the spool grip cover 25 clockwise.
NOTE: Do not try to remove the spool by turning the spool housing 24 .
3. Remove spindle plate 30 before installing a new spool. Remove any dirt and grass from the motor housing and spindle plate.
4. Install spindle plate 30 onto the spindle 29 , so the double D shaped retaining nut on the spindle sits inside the base of the spindle plate.
5. Align the spindle plate hole and notch, insert a screwdriver back into the hole and thread the new spool housing counterclockwise. Securely tighten the new spool housing onto the spindle 29 .
Replacing Guard (Fig. O)
An extended coverage guard is available (sold separately) for extra coverage if desired. Use DEWALT replacement guard Part Number N890579.
⚠️ WARNING: Never operate appliance without guard firmly in place.
1. Remove the 2 guard screws 19 .
2. Attach the new guard as described in the Attaching Guard section.
Folding for Storage or Transportation (Fig. A, B, P)
The string trimmer can be folded for storage or transportation. To put the string trimmer in the folded position, please refer to Extending and Folding the Pole.
Repairs
The charger and batteries are not serviceable. There are no serviceable parts inside the charger or battery pack.
⚠️ WARNING: To assure product SAFETY and RELIABILITY, repairs, maintenance and adjustment (including brush inspection and replacement, when applicable) should be performed by a factory service center or an 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/account-login.
Three-Year Limited Warranty
For warranty terms, go to www.dewalt.com/support/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.
