the safety guard on my dewalt saw is stuck and won't retract automatically when i start a cut.

Diagnosis

The lower blade guard on the DeWalt DCS570B utilizes a heavy-duty pivot arm and a tension spring designed to snap the guard shut instantly. When the guard fails to retract, it is almost always due to "debris packing." Fine sawdust mixes with resin or moisture, creating a hardened crust inside the pivot assembly or between the guard's trailing edge and the metal base plate (shoe). This creates enough friction to overcome the force of the blade pushing the guard open. In some cases, if you have been cutting pressure-treated lumber or composite decking, chemical residues can act as an adhesive, effectively gluing the guard in the closed position. You can confirm this is the issue by disconnecting the battery and attempting to manually retract the guard using the thumb lever. If the lever moves but the guard lags behind or feels "gritty," the obstruction is located within the pivot pin or the guide channel. If the lever itself is frozen, the jam is likely located in the external linkage arm.

How to Fix It

Follow these steps to restore the guard's automatic function. Ensure the 20V Max battery is removed before starting to prevent accidental startup.

1. Clear the Pivot Point: Use a stiff nylon brush or a handheld vacuum to remove all loose sawdust from the area where the lower guard attaches to the main housing. Focus specifically on the gap between the guard's pivot arm and the saw's chassis.
2. Deep Clean the Guide Channel: Use a can of compressed air with the straw attachment. Insert the straw directly into the pivot joint and blast air in short bursts while manually cycling the guard open and closed. This breaks up the compacted "cakes" of sawdust.
3. Inspect the Shoe Clearance: Check the area where the bottom of the guard rests against the base plate. If you see a buildup of pitch or resin, use a small plastic scraper or a microfiber cloth dampened with a small amount of isopropyl alcohol to clean the metal surface of the shoe.
4. Lubricate the Pivot: Apply a very small amount of dry PTFE lubricant or graphite powder to the pivot pin. Do not use WD-40 or wet oils, as these attract more sawdust and will cause the guard to jam again within a few cuts.
5. Test Cycle: With the battery still removed, flip the guard open and shut ten times rapidly. It should snap back with a distinct "clack" sound. If it lingers or slides slowly, repeat the compressed air process.

If That Didn't Work

• Check for Bent Linkage: Inspect the thin metal arm that connects the thumb lever to the guard. If the saw was dropped or the guard was forced backward during a kickback event, the arm may be slightly bowed. Use pliers to gently straighten the arm, ensuring it moves freely without rubbing against the motor housing.
• Inspect the Return Spring: If the guard retracts but does not snap shut, the internal tension spring may have lost its temper or become detached. This requires removing the pivot bolt (usually a 10mm or T20 Torx depending on the production run) to reseat the spring.
• Remove Blade Obstructions: Occasionally, a warped blade or a blade with a damaged flange can rub against the guard's inner wall, creating mechanical resistance. Swap the blade for a known straight 6-1/2" blade to see if the guard operation improves.
• Clear the Shoe Adjustment: Ensure the bevel adjustment lock is tight. If the base plate is slightly skewed or loose, it can put the guard at an odd angle relative to the shoe, causing it to bind during the initial push of a cut.

Heads Up

• Never Tape the Guard: Never use tape or clamps to hold the guard open. This disables a critical safety feature and can lead to severe injury if the saw kicks back.
• Blow-Out Maintenance: Make it a habit to blow out the guard pivot with compressed air every 5-10 boards, especially when cutting pine or cedar, which produce sticky resins.
• Avoid Solvent Overuse: Do not soak the guard assembly in harsh chemical solvents, as this can degrade the plastic components of the 20V Max housing.
• Check Blade Tightness: Always ensure your blade is torqued correctly; a loose blade can wobble, causing the guard to snag unpredictably during operation.