How To Drill Out A Rivet: Complete Technical Removal Guide

Removing a blind or solid rivet cleanly requires placing an accurate center punch mark in the middle of the rivet head, selecting a drill bit matched exactly to the rivet shank diameter, and drilling only deep enough to pop the head off without enlarging the host hole. Using cobalt or high-speed steel bits at controlled drill speeds preserves the structural integrity of the surrounding sheet metal, allowing for easy fastener replacement across automotive, aerospace, and general fabrication projects.

Pre-Operation Setup & Rivet Removal Equipment Checklist

Drilling out a rivet is a standard mechanical operation used in sheet metal repair, racecar maintenance, boat restoration, and HVAC ductwork. Fastener removal relies on isolating the soft rivet body (typically aluminum, copper, mild steel, or stainless steel) from the base material. The objective is to shear the mechanical bond holding the manufactured head to the expandable shank without cutting into the parent sheet metal or ovalizing the installation hole.

Before applying power tools to a workpiece, inspect the fastener assembly. Determine whether you are dealing with a blind pop rivet, a solid aircraft rivet, or a heavy-duty structural cherrylock rivet. Blind rivets feature a hollow center (often containing a snapped steel mandrel stem), whereas solid rivets possess a solid metal head and shank. Identifying the alloy composition determines the required cutting bit material, lubrication needs, and rotational speed (RPM).

+-----------------------------------------------------------------------------------+ | EQUIPMENT & TECHNICAL REQUIREMENTS CHECKLIST | +-----------------------------------------------------------------------------------+ | Mandatory Gear & Hardware: | | * Variable-speed hand drill (cordless or pneumatic) | | * High-Speed Steel (HSS) or M42 8% Cobalt drill bits | | * Automatic spring-loaded center punch | | * Parallel-pin punch set (1/16-inch to 3/16-inch tip diameters) | | * Ball-peen hammer (8 oz to 16 oz) | | * Cutting fluid, tap magic, or 3-In-One multi-purpose oil | | * ANSI Z87.1 approved safety glasses and cut-resistant gloves | | * Cold chisel or thin flathead screwdriver (optional) | | | | Prerequisite Technical Knowledge & Standards: | | * Wire gauge and fractional drill bit sizing standards (NAS 523 / SAE guidelines) | | * Fastener head identification ( countersunk 100° vs. universal button head) | | * Material hardness hierarchy (Cobalt bits required for stainless steel rivets) | | | | Operational Benchmarks: | | * Estimated Cost: $15–$45 for consumable bits and basic hand tools | | * Time Requirement: 2 to 5 minutes per fastener | +-----------------------------------------------------------------------------------+

The Precision Guide to Drilling Out Blind and Solid Rivets

Step 1: Identify Fastener Dimensions and Match Bit Geometry

Accurately determine the diameter of the rivet body. Measuring only the outer flared head will result in selecting an oversized drill bit, which cuts directly into the host panel and ruins the joint clearance. Use dial calipers across an exposed rear shank if accessible, or consult standard trade sizing charts.

For standard 1/8-inch (0.125 in) rivets, select a number 30 wire gauge drill bit (0.1285 in) or a standard 1/8-inch HSS bit. For 5/32-inch rivets, select a number 21 bit (0.1590 in). For 3/16-inch rivets, select a number 11 bit (0.1910 in). Matching the bit size to the shank body ensures you only weaken the neck joint connecting the head to the body.

Pro-Tip: Standard fractional drill bits work for general utility, but using number-wire gauge bits (such as #30, #21, and #11) provides slightly better clearance when working on precision sheet metal assemblies, preventing the bit flutes from grabbing the sidewalls.

Step 2: Drive Out Trapped Mandrel Stems and Center Punch

In blind pop rivets, a portion of the steel pulling stem (mandrel) often remains locked inside the center core. Because steel is significantly harder than an aluminum rivet body, attempting to drill directly over a trapped mandrel pin causes the drill bit to walk off-center and ruin the surrounding sheet metal.

1. Place a small drive pin punch (1/16-inch or smaller) directly onto the center stem inside the rivet head.
2. Strike the pin punch sharply with an 8 oz hammer to drive the residual steel stem out through the back of the rivet assembly.
3. Position the tip of an automatic spring-loaded center punch dead-center on the rivet head.
4. Press down firmly until the internal spring trips, creating a distinct conical indentation in the exact center of the fastener head.

Warning: Never skip center-punching. A drill bit rotating on a smooth, rounded aluminum or steel rivet head will drift immediately across the workpiece, scoring the finished surface and compromising structural tolerances.

Step 3: Apply Cutting Lubricant and Set Equipment Speed

Heat buildup dulls drill bits and causes soft aluminum to gall, sticking to the cutting flutes and gouging the workpiece. Apply one or two drops of cutting fluid directly onto the center-punched divot.

Adjust your variable-speed drill according to the rivet material:

• Aluminum Rivets: Run at medium-to-high speeds (1,500 – 2,500 RPM) with light, steady pressure.
• Mild Steel Rivets: Run at moderate speeds (800 – 1,200 RPM) with firm, constant pressure.
• Stainless Steel or Monel Rivets: Run at low speeds (300 – 600 RPM) with heavy axial pressure using an M42 Cobalt drill bit to prevent work-hardening the alloy.

Step 4: Drill Through the Rivet Head Junction

Hold the drill strictly perpendicular (at a 90-degree angle) to the sheet metal surface. Align the drill bit tip directly into the center-punched dimple.

DRILL BIT ||| ||| /-------\ <-- Rivet Head (Drill ONLY through this depth) ================= <-- Sheet Metal Panel 1 ================= <-- Sheet Metal Panel 2 | ||| | | ||| | <-- Rivet Shank / Body \_______/

1. Engage the drill trigger and apply light forward pressure along the centerline of the bit.
2. Maintain rigid wrist stability to prevent the bit from tilting off-axis.
3. Drill steadily into the head until the drill bit reaches the depth where the rounded head meets the flat surface of the sheet metal panel.
4. Watch for the moment the ring of the rivet head detaches from the shank. The head will frequently climb up the drill bit flutes and spin freely.

Pro-Tip: Stop drilling the millisecond the rivet head pops loose or begins spinning on the bit. Do not drill entirely through the joint with the removal bit; cutting too deep will enlarge the hole in the parent sheet metal, making it impossible to install a replacement rivet of the original size.

Step 5: Separate the Head and Drive Out the Remaining Shank

Once the rivet head breaks free from the shank:

1. Retract the drill bit while keeping the motor spinning to clear metal shavings.
2. If the head remains partially attached by a small burr, slip the edge of a thin cold chisel or flathead screwdriver beneath the rim and twist gently to pop it off.
3. Select a pin punch with a tip diameter slightly smaller than the rivet shank (e.g., a 3/32-inch pin punch for a 1/8-inch rivet).
4. Insert the pin punch into the hollow center where the head was removed and tap it firmly with a hammer to push the expanded shank out through the back of the panel structure.
5. De-burr the edge of the original mounting hole using a manual deburring tool or a countersink bit turned by hand.

Drill Bit Selection & Rivet Specification Compatibility

Choosing the correct bit size and material prevents tool breakage and preserves host panel integrity. The following reference chart details matching drill bit specs, recommended drill speeds, and pin punch sizes across standard industrial rivet dimensions.

Field Failure Modes and Structural Recovery Fixes

Even with precise measurement, fastener removal can encounter complications due to material corrosion, off-center tool placement, or spinning fasteners. Use these technical recovery protocols to fix common shop errors.

Scenario 1: The Host Sheet Metal Hole is Ovalized or Enlarged

• Root Cause: The operator held the drill at an angle, used an oversized bit, or allowed the drill bit flutes to bite into the parent panel walls after the head popped off.
• Actionable Fix: Step up to the next standardized oversized rivet size. If a 1/8-inch hole was wallowed out to 0.145 inches, ream the hole cleanly with a #21 drill bit and install a 5/32-inch replacement rivet. If stepping up a size is not structurally permitted by design engineering specs, install a structural backing washer or utilize an approved oversize shank rivet (such as a NAS1097 series flush rivet with an enlarged shank).

Scenario 2: The Rivet Head Spins with the Drill Bit

• Root Cause: The clamping force between the rivet shop head and the sheet metal has been broken, eliminating friction. The rivet rotates at the same RPM as the bit, preventing the cutting edges from shaving metal.
• Actionable Fix: Slide the thin blade of a pocket knife, narrow chisel, or flathead screwdriver underneath the lip of the spinning rivet head to apply leverage and wedge it stationary against the panel. Alternatively, apply a strip of heavy duct tape over the head or clamp locking needle-nose pliers onto the head rim to lock it in place while reapplying the drill bit under low rotation speed.

Scenario 3: Broken Drill Bit Core Trapped Inside Fastener

• Root Cause: Excessive lateral side-loading on a small-diameter bit or failure to use cutting fluid on hard steel rivets, causing the bit to snap flush inside the rivet center.
• Actionable Fix: High-speed steel drill bits are extremely hard and cannot be drilled out with standard bits. Place a hardened carbide-tipped scribe or small punch against the broken bit fragment and tap it gently with a hammer to shatter or dislodge the piece. If accessible from the back, drive the fragment out toward the front. If flush, use a high-speed rotary tool equipped with a miniature diamond-coated spherical burr to grind away the hardened center pin before resuming drilling.

Scenario 4: Hardened Steel Mandrel Stem Cannot Be Punched Out

• Root Cause: Corrosion, galling, or severe mandrel deformation inside a structural blind pop rivet locks the steel stem inside the softer aluminum sleeve.
• Actionable Fix: Grind a small flat spot onto the exposed rounded top of the stem using a hand file or rotary grinding stone. Mark the exact center of the steel pin with a heavy-duty center punch. Use a small, high-quality carbide or cobalt stub-length drill bit (1/16-inch diameter) to drill a pilot hole directly through the length of the trapped mandrel stem, relaxing its internal expansion tension so it can be punched out cleanly with a pin punch.

Frequently Asked Questions

What size drill bit do I need to drill out a standard 1/8-inch pop rivet?

Use a #30 wire gauge drill bit (0.1285 inch) or a standard 1/8-inch (0.1250 inch) drill bit. A #30 bit is preferred in metal fabrication because its slight over-clearance prevents the bit from binding in the rivet head while maintaining the original 1/8-inch host hole dimensions without damaging the sheet metal.

Can you drill out a rivet without an automatic center punch?

While possible, skipping a center punch significantly increases the risk of damaging your workpiece. If an automatic punch is unavailable, use a standard manual center punch and a light hammer, or use a sharp nail to tap a tiny starter indentation in the exact geometric center of the rivet head to keep the drill bit centered.

How do you drill out stainless steel or solid steel rivets compared to aluminum?

Drilling steel rivets requires high-heat-resistant M42 cobalt drill bits, reduced drill motor speeds (300 to 800 RPM), high axial feed pressure, and continuous application of cutting fluid. Fast speeds will instantly work-harden stainless steel, dulling HSS bits and making removal significantly harder.

How do I remove a rivet if I don't have access to the backside of the panel?

Drill off the rivet head from the front using standard techniques until the ring pops free. Once the head is removed, place a pin punch (sized to match the shank) into the open center and tap it firmly; the remaining shank will drop harmlessly behind the blind wall or structure inside the unexposed cavity.

Will drilling out a rivet permanently enlarge the existing hole?

No, provided you stop drilling as soon as the rivet head separates from the shank. The drill bit should only penetrate the thickness of the head. The remaining body of the fastener is then pushed through with a pin punch, leaving the original mounting hole intact and ready for a replacement rivet of the same size.

Professional Fastener Removal & Sheet Metal Repair Tools

Achieving clean, damage-free fastener removal relies on using hard-wearing tools designed for structural metalwork. Equip your workshop with precision-ground cobalt bits, automatic center punches, and specialized pneumatic rivet tools to maintain strict assembly tolerances during panel restoration and structural repairs.