Symptoms
- Screw head ends up at a slight angle
- Bit cams out of the screw head partway through
- Screw wanders as it goes in
- Screw won't seat flush despite full trigger pressure
Likely causes
- CommonDrill held at a slight angle instead of perpendicular to the surfaceEven a small tilt compounds as the screw goes deeper.
- CommonWrong size or type of driver bit for the screw headA loose-fitting bit slips and lets the screw drift instead of driving straight.
- PossibleNo pilot hole in hardwood or dense materialScrews can deflect off the wood grain without a starter hole.
- PossibleToo much speed and not enough control at the startStarting too fast before the screw is seated makes it harder to keep aligned.
- PossibleWorn or rounded driver bit tipA worn bit slips (cams out) instead of transferring torque evenly.
What to do
- Start the screw by hand a few turns if possible, or use a self-centering screw starter, before powering in.
- Hold the drill perpendicular to the surface and sight down the bit to check alignment before starting.
- Match the driver bit exactly to the screw head type and size (not a close-enough fit).
- Drill a pilot hole for larger screws in hardwood or near the edge of a board to prevent splitting and wandering.
- Start at low speed until the screw bites, then increase speed to drive it home.
- Replace driver bits at the first sign of rounding; they're inexpensive and a worn tip causes most crooked or stripped screws.
Tools and parts
- Pilot hole drill bit
- Fresh driver bits
Driver bit set matched to screw typeSearch: “screwdriver bit set for drill”
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.