it sounds like there's gravel rolling around inside my jigsaw when i shake it.

Diagnosis

The "gravel" sound inside your DeWalt 20V Max Jigsaw DCS334B is almost always the result of accumulated metallic debris or fragmented carbon brush material. Because the DCS334B utilizes an open-vented motor design to dissipate heat during heavy cuts, fine sawdust and metal shavings from cutting aluminum or steel profiles are sucked into the housing by the internal cooling fan. Over time, these particles settle at the bottom of the plastic chassis, and as they oxidize or clump together, they create a rattling sound similar to small pebbles or gravel.

In some specific cases, this sound indicates that a piece of the internal plastic casting has snapped or that a carbon brush has completely disintegrated, leaving chunks of graphite rolling around the motor assembly. To confirm the source, hold the tool firmly and tilt it slowly 90 degrees in each direction. If the sound is localized near the rear of the motor housing, it is likely carbon dust; if it rattles near the front gear housing, it is likely external debris or a failing bearing race. If the tool is still operating at full speed and without abnormal grinding noises, it is almost certainly harmless debris rather than a catastrophic mechanical failure.

How to Fix It

To clear the internal housing of the DCS334B without a full teardown, follow these precise steps:

1. Remove the 20V Max battery pack and set it aside to ensure the trigger cannot be accidentally engaged.
2. Secure the jigsaw in a vice by the base plate or hold it firmly over a large waste bin, tilting the motor housing downward.
3. Using a high-pressure compressed air canister or a shop compressor with a narrow nozzle (minimum 30 PSI), blast air directly into the motor vents located on the sides and rear of the tool.
4. Focus specifically on the gaps around the trigger assembly and the battery terminal port, as debris often migrates toward these openings.
5. While applying air, shake the tool vigorously in a side-to-side motion to dislodge particles that have adhered to the plastic floor of the housing.
6. Rotate the tool 180 degrees and repeat the process, ensuring you clear the area around the orbital action switch.
7. Insert the battery and run the tool at full speed for 10 seconds to allow the centrifugal force of the motor to shift any remaining loose particles toward the vents.

If That Didn't Work

• Full Housing Purge: If compressed air fails, you must remove the external housing. Use a T15 Torx driver to remove the screws securing the plastic shell. Carefully peel back the housing to expose the motor and gear assembly. Use a vacuum with a brush attachment to suck out the "gravel" directly from the bottom of the casing. Be careful not to touch the copper windings of the motor.
• Carbon Brush Inspection: If the rattling persists and the tool feels sluggish, the carbon brushes may be worn down to the spring. Remove the brush caps at the rear of the motor. If the brushes are shorter than 5mm or fragmented, replace them with a genuine DeWalt brush set to prevent damage to the commutator.
• Bearing Race Check: If the sound is accompanied by a high-pitched whine, a ball bearing in the gear housing may have failed, releasing a steel ball. In this case, the gear housing must be disassembled, and the bearing replaced. This requires a bearing puller and a press to avoid damaging the shaft.
• Magnetic Debris Removal: If you frequently cut non-ferrous metals, use a strong neodymium magnet wrapped in a thin cloth. Slide it along the exterior vents and battery port to see if you can attract any metallic shards that are stuck to the internal plastic walls.

Heads Up

• Avoid Wet Cleaning: Never use liquid cleaners or solvents inside the motor housing, as this will cause the metallic debris to rust and bond to the motor windings, leading to a short circuit.
• Vent Maintenance: Every 20 hours of heavy use, blow out the vents with air. Preventing buildup is significantly easier than removing "gravel" once it has clumped.
• Blade Selection: Ensure you are using the correct T-shank blades for the material. Using a wood blade on metal creates excessive fine-particle shavings that are more likely to enter the motor housing.
• Battery Port Care: Always check the battery terminals for debris before sliding in a battery; particles trapped in the port can cause intermittent power loss or sparking.