Metal wall anchors grip hollow drywall by expanding behind it, and you install them by drilling the right size hole, setting the anchor, and tightening until snug.
Hanging a shelf or TV mount on drywall fails when you skip the anchor and rely on a screw alone. Knowing how to use metal wall anchors is the difference between a fixture that holds for years and a hole in the wall. The principle is simple: the anchor’s wings expand behind the wall surface, spreading the load so the screw doesn’t tear through. Here is the exact method that works.
What Are Metal Wall Anchors?
Metal wall anchors are hollow-wall fasteners, and the most common type is the toggle bolt — a machine bolt paired with spring-loaded wings. The wings fold flat against the bolt for insertion, then spring open once they clear the back side of the drywall. These anchors are built for hollow materials like drywall and plaster, where there is an empty cavity behind the surface. The expanded wings press against the back of the wall, spreading the fixture’s weight across a wider area than a plain screw ever could.
How to Install a Toggle Bolt Step by Step
Installing a metal toggle anchor takes about two minutes once you have the right drill bit. Follow this order and the anchor will seat correctly the first time.
- Drill the hole. The hole must be slightly larger than the folded toggle so the wings can pass through. Check the anchor’s packaging for the exact bit size; a standard high-speed steel twist bit works for drywall and plaster.
- Pass the bolt through the fixture. Put the bolt through the hole in your shelf bracket or wall mount before inserting the anchor into the wall.
- Thread on the wings. Screw the spring-loaded wings onto the bolt until they sit flush against the fixture, then fold them flat.
- Insert through the hole. Push the folded wings into the hole until they clear the back of the wall. You will feel them spring open.
- Pull back and tighten. Pull the bolt toward you so the wings seat firmly against the back of the wall. Tighten until the fixture is snug.
What success looks like: the bracket sits flat and flush, and the bolt turns smoothly with no wobble.
Installation Rules That Prevent Failure
Two rules account for most toggle-bolt failures. The first is hole size: if too small, the folded wings cannot pass through and you will crush the drywall forcing them. The second is tightening.
Do not overtighten. This is the single biggest mistake. Stop turning as soon as the fixture feels snug. Overtightening strips the anchor’s grip or pulls the wings through the drywall. Some toggle designs require you to hold the bolt in tension while tightening so the wings stay seated — if the bolt spins freely, apply light outward pressure while you turn.
Steel is different — a wall anchor sold for drywall may not penetrate wood or metal studs, so locate studs first and do not install anchors at stud marks. If you need anchors engineered for metal surfaces, our tested roundup of anchors for metal covers the options that hold up.
Quick Reference: Bit Size and Material
| Wall Material | Drill Bit Type | Hole Size Rule |
|---|---|---|
| Drywall or plaster | High-speed steel twist bit | Slightly larger than folded toggle |
| Hollow block | Masonry bit | Same as folded toggle width |
| Masonry or high-strength concrete | Masonry bit | 1/16 inch larger than base material spec |
| Wood or metal studs | Standard wood or metal bit | Do not use anchors — screw directly into stud |
Load ratings vary widely by model and wall type. A small toggle rated for lightweight pictures will not hold a heavy mirror, and a high-capacity anchor in thin drywall will still fail. Treat the listed weight limit as the maximum for a solid installation, not a suggestion.
FAQs
Do I need a special drill bit for metal wall anchors?
No — a standard high-speed steel twist bit in the size listed on the anchor package works for drywall and plaster. For hollow block, masonry, or high-strength concrete, switch to a masonry bit, and for masonry drill the hole 1/16 inch larger than the base material spec calls for.
Why does my toggle bolt keep spinning in the wall?
The bolt spins when the wings are not seated firmly against the back of the wall. Pull the bolt toward you with light outward tension while tightening. If it still spins, the hole may be too large or the wings may have folded back into the cavity — remove the bolt, refold the wings, and try again.
Can I use metal wall anchors in concrete?
Standard toggle-bolt anchors are designed for hollow walls, not solid concrete. For masonry and high-strength concrete, use a masonry bit to drill the hole 1/16 inch larger than required, and choose a wedge or sleeve anchor made for solid materials. A drywall toggle will simply crush or fail in concrete.
References & Sources
- Florida Building Commission. “Installation Instructions for Toggle Bolt Anchors.” Details hole sizing and the 1/16-inch rule for masonry.
- Florida Building Commission. “Anchor System Installation Guide.” Covers the requirement to locate studs and avoid anchor placement at stud marks.