my avid power drill keeps stopping in the middle of driving a screw, feels like it's slipping

Diagnosis

This behavior is typically caused by the AUTOSENSE clutch system prematurely triggering a safety disengagement. In the Avid Power 20V series, the AUTOSENSE feature is designed to detect the specific resistance profile of a screw as it seats into the material. When the motor senses a spike in torque that mimics a fully driven screw, it cuts power to the drive train to prevent the screw head from stripping or the workpiece from cracking. The "slipping" sensation you feel is the mechanical clutch decoupling the motor from the chuck. This happens most frequently when using oversized screws in dense hardwoods or when the drill bit is not perfectly centered in the screw head, causing a momentary "kick" that the sensor interprets as the end of the drive cycle. You can confirm this is a clutch issue if the motor continues to hum for a split second after the rotation stops, or if the tool resumes normal operation immediately after you release and re-press the trigger.

How to Fix It

To resolve this and ensure the drill completes the drive, follow these precise calibration and operational steps:

1. Verify Mode Selection: Locate the torque adjustment collar directly behind the chuck. Rotate the collar until the pointer aligns exactly with the screwdriver icon. If the collar is set to the drill bit icon (Bore Mode), the AUTOSENSE feature is bypassed, but you risk stripping the screw. For the "smart" stopping feature to function correctly, it must be in the screwdriver zone.
2. Reset the Trigger Cycle: When the drill stops mid-drive, do not keep the trigger squeezed. Completely release the trigger to reset the electronic control board. Wait one full second, then apply a steady, progressive squeeze.
3. Adjust Axial Pressure: The AUTOSENSE system relies on the relationship between rotational torque and forward pressure. Increase the physical force you are applying to push the drill into the screw. If you are leaning back or applying light pressure, the drill will "slip" because the torque spike is too high relative to the forward movement.
4. Check Bit Seating: Ensure you are using the correct driver bit (e.g., PH2 for standard Phillips). If the bit is slightly too small, it will wobble, creating erratic torque readings that trick the clutch into thinking the screw is seated.

If That Didn't Work

• Switch to Manual Torque Control: If the AUTOSENSE is too sensitive for your specific material, rotate the collar away from the "Auto" setting to one of the numbered torque settings (1-15). Start at a mid-range number like 7. This replaces the electronic sensing with a mechanical friction clutch that you can manually tune by turning the collar higher or lower until the screw drives fully without slipping.
• Pre-Drill Pilot Holes: If you are driving screws into hardwoods like oak or maple, the resistance is often too high for the 20V motor's sensor. Use a 1/16" or 1/8" drill bit to create a pilot hole. This reduces the initial torque requirement, preventing the clutch from triggering prematurely.
• Inspect Battery Charge Level: Low voltage in the 20V lithium-ion pack can cause inconsistent power delivery to the motor, which can lead to erratic clutch behavior. Swap the battery for a fully charged pack to see if the "slipping" persists.
• Check for Debris in the Collar: Sawdust and drywall mud can get packed into the gap between the torque collar and the main housing. Use a can of compressed air to blow out the collar area; if the collar cannot snap firmly into its detents, the tool may be caught between "Drill" and "Screwdriver" modes.

Heads Up

• Avoid Over-Torquing: When using the manual numbered settings, avoid staying on the highest setting (15) for long periods, as this puts significant strain on the planetary gears of the 20V gearbox.
• Bit Quality Matters: Cheap, soft-metal bits flex under pressure. This flex creates a "spring" effect that can trigger the AUTOSENSE clutch. Use impact-rated or hardened steel bits for a more consistent drive.
• Heat Management: If you have been driving many large screws, the motor may overheat. The internal thermal protection can sometimes mimic a clutch slip by reducing power. Let the tool cool for 10 minutes if the housing feels hot to the touch.
• Lubrication Warning: Never spray WD-40 or other lubricants into the torque collar or the chuck. This will attract grit and potentially degrade the plastic internals of the clutch system.