How to Remove Spot Welds with a Drill Bit Set

Quick Answer

Use a spot weld drill bit set with a centering nib and flat shank to cut through spot welds without walking or spinning in the chuck.

Step-by-Step: Removing Spot Welds

1. 1. Select the Right Bit Size: Choose a spot weld bit that matches the diameter of the weld nugget. A bit that is too small will not cut through; too large will remove surrounding metal. A 1/4" bit works for most automotive spot welds; use 5/16" for heavier welds on frames or brackets.
2. 2. Secure the Workpiece: Clamp the panel or part firmly so it cannot shift. Vibration or movement will cause the bit to wander and produce an uneven cut. If you cannot clamp the piece, use a vacuum pad or have a helper hold steady pressure.
3. 3. Position the Bit on the Weld: Align the centering nib of the bit directly over the center of the spot weld. Apply light downward pressure before starting the drill. Do not start the drill until the nib is seated; otherwise the bit may skip off the weld.
4. 4. Drill at Medium Speed: Run the drill at 1000–1500 RPM (medium speed) with steady, moderate pressure. Let the bit do the cutting—do not force it. Excessive speed or pressure can overheat the bit and dull the cobalt edge prematurely.
5. 5. Stop When the Weld Separates: As soon as the bit breaks through the weld and you feel the panel separate, stop drilling immediately. Continuing will cut into the underlying metal. If the weld does not separate after a few seconds, recheck your bit size—you may need the next larger diameter.
6. 6. Clean Up the Hole: Use a deburring tool or a light file to remove any sharp edges left around the hole. This prevents injury and makes for a cleaner weld prep if you are re-welding. A quick pass with a countersink bit can also clean the hole edge in one motion.

Recommended Product

• Drill Hog® 3 Pc Spot Weld Drill Bit Set: Includes 3 spot weld bits in 3/8", 1/4", and 5/16" sizes, machined from solid Super Premium Cobalt M42 Steel. The cobalt steel holds an edge longer than HSS when cutting through multiple spot welds, and the three sizes let you match the weld diameter without over-drilling.