DeWalt 20V Max 14″ String Trimmer

Safety

The DCST922 is a fast-cutting trimmer, not a light garden toy. The flexible line can throw stones, wire, mulch, and hard stems well beyond the cutting swath. Wear eye protection, long pants, gloves, and sturdy footwear. Keep the guard installed; removing it exposes more line than the motor and operator can safely manage. Install the battery only after the shaft is locked and the head is clear of hands, clothing, and loose cord.

• Keep bystanders and pets at least 50 ft away.
• Use only 0.080–0.095″ trimmer line.
• Do not run without the guard and line cutter.
• Keep the head below waist height during trimming.
• Remove the 20V Max battery before clearing wraps, changing line, folding, or transporting.
• Avoid wet grass when footing is poor or electrical hazards are nearby.

Unboxing & first run

Unpack the trimmer, guard, auxiliary handle, any included spool, and charger or battery kit components. Inspect the telescoping straight shaft for shipping damage and confirm the hinge or folding joint locks firmly. The guard must be installed before the first run because it sets the safe line length and blocks debris. Do not test-spin the head indoors.

• Fit the guard and tighten its screws until secure; do not overtighten into plastic.
• Install the auxiliary handle where the front hand can stay relaxed with elbows slightly bent.
• Extend the shaft until posture is upright and the head sits flat near the ground.
• Load 0.080″ or 0.095″ line according to spool direction.
• Insert a charged 20V Max battery.
• Start in open grass, use low speed first, and bump-feed only while the head is spinning.

Controls layout

The DCST922 places the main controls at the rear handle and the balance controls along the shaft. The trigger starts the motor only when the lock-off is held, reducing accidental starts during carrying. The speed selector, when fitted on the handle assembly, lets the operator trade runtime for cutting power. The auxiliary handle and telescoping shaft are adjustment points, not carrying hooks.

• Rear handle: trigger, lock-off, and primary right-hand control.
• Speed selector: choose lower speed for edging grass, higher speed for dense weeds.
• Auxiliary handle: set for a neutral wrist and level cutting head.
• Telescoping straight shaft: adjust length before installing the battery.
• Folding joint: lock fully before operation or transport.
• Guard and line cutter: maintain the designed 14″ cutting swath.
• Bump head: advances line when tapped on firm ground under power.

Routine maintenance

Routine care is mostly debris control and line management. Grass sap and dust collect around the spool, vents, guard, and shaft joint, then harden into drag. Remove the battery before cleaning. Do not hose the motor housing or soak the head; water carries grit into bearings and switches. For frequent edging, inspect the guard and line cutter more often because concrete abrasion changes line behavior.

• Brush vents clear after dusty or dry cutting.
• Remove wound grass from the shaft above the head.
• Check the spool cap tabs for cracks or worn latch edges.
• Keep line diameter within 0.080–0.095″.
• Replace brittle, kinked, or heat-glazed line.
• Confirm the telescoping shaft clamp and folding latch lock securely.
• Store with the battery removed and the head free of pressure.

Blade or chain replacement

This trimmer does not use a saw chain; the service item is the cutting line, spool, or bump-feed head. Use line within the specified 0.080–0.095″ range. Oversize line increases motor load and can shorten runtime, while undersize line breaks frequently and feeds poorly. If the bump head is cracked, loose, or no longer holds line, replace the head before using the tool near windows, vehicles, or finished surfaces.

• Remove the battery and place the trimmer on a bench.
• Press the spool-cap tabs and lift off the cap.
• Remove leftover line and clean dust from the spool pocket.
• Wind new line in the marked direction without crossing layers.
• Leave equal line tails through both eyelets.
• Refit the cap until both tabs click.
• Trim excess line with the guard cutter during the first spin-up, not with a knife near the head.

Sharpening or cleaning

Trimmer line is not sharpened; clean feeding parts and replace worn line instead. A dull or nicked guard-mounted line cutter can leave the swath uneven, but it is usually replaced rather than filed. Cleaning matters most after wet grass, seed heads, and viney weeds because wraps under the head can load the shaft and make the tool feel weak.

• Remove the battery before touching the head or guard.
• Pull wrapped grass and vine stems away from the spindle area.
• Brush the spool, eyelets, cap, and line cutter clean.
• Wash only removable plastic parts by hand, then dry completely before assembly.
• Replace line that has welded together inside the spool.
• Inspect the guard for cracks around screw bosses.
• Keep ventilation slots open; blocked cooling turns a line problem into an electrical shutdown.

Troubleshooting

Start diagnosis with line length and battery state. A trimmer with short line may seem weak because it is cutting with only one side of the head, while excess line beyond the cutter overloads the motor. Remove the battery before checking the spool. Reinstall it only for a brief outdoor test.

• Motor does not start: confirm the battery is latched, charged, and the lock-off is fully pressed.
• Vibration: remove the spool and clear uneven line, packed grass, or cracked cap parts.
• Line will not feed: check winding direction, line diameter, and eyelet wear.
• Line breaks often: reduce contact with fences, brick, and concrete; use fresh 0.095″ line for heavier weeds.
• Short runtime: use lower speed, lighter feed pressure, and clean vents.
• Shaft feels loose: stop and relock the telescoping clamp or folding joint.

Compatible parts

Choose parts around the 14″ trimmer head and the specified 0.080–0.095″ line range. The DCST922 can trim light lawn edges with thinner line, but heavier weeds and fence-line work benefit from 0.095″ line if runtime remains acceptable. Do not fit brush blades, metal chains, or improvised heads unless the tool maker specifically approves them for this model.

• AP—BF14—HEAD: compatible bump-feed head for the 14″ trimmer platform.
• AP—095—LS: replacement 0.095″ trimmer line for heavier trimming.
• AP—EYE—DW14: replacement eyelet set for worn or grooved feed ports.
• Confirm the head thread and mounting style before replacing the assembly.
• Replace the cap, spool, and eyelets as a set if feeding remains unreliable after cleaning.