An impact driver is useful for driving intact fasteners. It is not the first tool to reach for when the recess is already rounded. Extra impact can remove the last usable edges, break the screw below the surface, or damage the fixture.

Check the model type before buying: DCD796P2 is a drill/hammer-drill kit rather than a 1/4-inch impact driver, and Milwaukee 2767-20 is an impact wrench rather than a 1/4-inch hex driver.

Use the least destructive method first

  1. Stop as soon as the bit cams out repeatedly.
  2. Clean paint, debris, rust or finish from the recess.
  3. Seat a new bit of the exact drive type and size. Pozidriv and Phillips are not interchangeable; neither are Torx sizes.
  4. Apply firm pressure in line with the screw and turn slowly.
  5. If the head stands proud, use suitable locking pliers without damaging the surrounding surface.
  6. For a recessed or badly rounded head, use a correctly sized extractor or drill-out method made for the fastener and material.

Penetrating oil may help a corroded metal-to-metal thread if the product is suitable for the surrounding material. It will not repair a damaged recess. Heat can create fire, finish, plastic and hidden-service hazards and should not be improvised.

Where an impact driver fits

A controlled impact driver can help with a tight fastener only while the bit still engages securely and the material can tolerate impact. Use an impact-rated bit, the lowest useful mode, firm alignment and short trigger pulls. Stop if the recess deforms, the head tilts, or the fastener stops progressing.

DEWALT lists the DCF845B as a 20V MAX XR three-speed 1/4-inch impact driver. That is a verified example of the tool class, not a claim that it will remove every stripped screw. It is sold as a bare tool, so battery and charger compatibility affect the purchase.

We have not tested it for extraction. The exact-model Amazon search is provided for buyers who already need an impact driver for ordinary fastening; it should not turn a single damaged screw into an unnecessary tool purchase.

Stop before the repair becomes larger

Pause when the screw secures plumbing, electrical equipment, glazing, a structural connector, or an expensive finished surface. Also stop when the fastener is broken below the surface or when drilling could hit hidden services.

Protect the workpiece before cutting a slot, drilling the head, or using an extractor. Extractors are hard and can be difficult to drill if they snap. For a high-value part, a repair shop or trade professional may be cheaper than replacing damage caused by one fastener.

Sources

Checked September 19, 2026: DEWALT current impact-driver catalog . The current DCF845 identity is documented; no stripped-screw extraction performance test was performed.