How to Remove a One-Way Screw (4 Methods, Ranked)

One-way screws are designed to go in but not come out — which is exactly the problem the first time you need to service, replace or remove whatever they're holding on. This guide covers what a one-way screw actually is, four real removal methods ranked from least to most destructive, and how to tell which one fits your job. Browse the full one-way screws range AIMS stocks while you're here.

Removing a One-Way Screw — Quick Reference

Start at the top of this table and only move down if the previous method fails. Every method below it does more damage to the screw and, potentially, to the surrounding material.

What is a one-way screw, and why won't it turn?

A one-way screw (also called a clutch-head screw, after its distinctive rounded, ramped slot) is built to defeat exactly the tool you'd normally reach for. The slot isn't symmetrical: one side is a near-vertical wall, the other is a shallow, chamfered ramp. Drive it clockwise with a standard flat-blade screwdriver and the blade sits against the steep wall and bites in normally. Try to back it out anti-clockwise and the blade rides up the ramp instead — the applied force gets redirected outward rather than into the screw, so the driver "cams out" and slips before it can generate any real turning force. No amount of extra pressure on a standard screwdriver fixes this; it's a geometry problem, not a grip problem.

They're a genuine security fastener rather than a novelty — once installed, a one-way screw can't be backed out with anything designed to fit its own slot. In Australia they turn up most often on number plates, playground and public-park equipment, street furniture and signage, security enclosures, and anywhere else a business or council wants a fastener the public can install-and-forget but not casually remove.

Method 1: Use a dedicated one-way screw removal tool

This is the only method on this list that doesn't damage the screw, so it's the right first attempt whenever the head is accessible. A one-way removal tool replaces the flat blade with two small, hardened points (carbide-tipped on better tools) set at the same spacing as the screw's ramped slot. Pressed firmly into the slot and turned anti-clockwise, the points dig into the ramp itself rather than sliding up it, giving the tool real purchase in the direction a standard screwdriver can't get.

1. Match the tool to the screw gauge — these tools are sized, and the wrong size won't seat properly in the slot.
2. Seat the tool fully in the slot and apply firm, steady downward pressure before turning — this is what lets the points bite rather than skate across the head.
3. Turn anti-clockwise with steady pressure maintained throughout, rather than a sharp twist.
4. If the screw doesn't move on firm hand pressure alone, a squirt of penetrating oil left to soak for 10–15 minutes before trying again solves most of the remainder — see our Penetrating Oil & Spray Lubricants Guide for what actually works on corroded fasteners.

AIMS stocks the Champion OWS-RT One Way Screw (Anti-Theft) Removal Tool for exactly this job.

Method 2: Locking pliers (mole grips)

Where the screw head has enough clearance above the surrounding surface to get a set of jaws around it, locking pliers are a genuinely effective low-cost fallback. Clamp directly onto the outer diameter of the head — not the slot — and let the serrated jaws bite into the metal for grip rather than relying on the slot geometry at all.

1. Clamp locking pliers tightly around the screw head's outer edge and turn anti-clockwise.
2. If the jaws slip on a smooth or rounded head, file two flat, parallel faces onto opposite sides of the head first — this gives the jaws something to bite that isn't round.
3. Working near a painted, powder-coated or otherwise finished surface, wrap a layer of aluminium flashing or masking tape around the screw first so the pliers' jaws can't mark the surrounding material if they slip.

This method won't work on a screw with a rotating hardened washer collar under the head (some higher-security variants use one specifically to defeat pliers), or on a flush or heavily recessed head with no clearance to grip.

Method 3: Cut a new slot

Converting the head to a standard flat-blade screw is the move for a head that's too recessed or tight-clearance for pliers to reach, but still accessible enough to get a cutting tool onto.

1. Using a rotary tool (a thin abrasive or cut-off wheel suits this better than a burr) or, for a screw proud of the surface, a hacksaw blade, cut a single straight slot across the full diameter of the head.
2. Cut to a consistent depth — deep enough for a screwdriver blade to seat properly, but no deeper than necessary given what's directly beneath the screw.
3. Once the slot is cut, back the screw out with an ordinary flat-blade screwdriver sized to the new slot.

Work slowly and keep the cutting wheel or blade square to the head — a cut that wanders can damage the surrounding surface, particularly on a painted or laminated material. This method permanently alters the screw; if it's a security screw doing a security job, budget on replacing it (see below).

Method 4: Drill it out (last resort)

Reach for this only once the methods above have genuinely failed, or on a head that's already corroded, rounded off or otherwise too damaged to grip by any other means — it destroys the screw and, on anything but a dead-centre pilot hole, risks damaging the surrounding thread or material.

1. Centre-punch the middle of the screw head to stop the drill bit wandering.
2. Drill straight down through the head with a bit roughly a quarter of the head's diameter, just deep enough to remove the head — not so deep you drill into whatever the screw is threaded into.
3. Once the head separates, the fixture or panel should lift free; back the remaining shank out with locking pliers, or, if it's seized in a tapped hole, with a screw extractor.
4. For a shank that shears off flush or won't grip with pliers, our Bolt Extractor Guide covers left-hand drill bits and Easy-Out-style extractors in detail.

Which method should I use?

Start with the dedicated removal tool whenever the head is reachable — it's the only non-destructive option and, for the cost of one tool, pays for itself the first time you'd otherwise have replaced a whole fixture. Step down to locking pliers if you don't have the tool on hand and the head has clearance to grip. Reach for cutting a new slot on a recessed head where pliers can't get purchase. Keep drilling as the genuine last resort — for a screw that's already corroded solid, badly rounded, or where the first three methods have already failed and made the head worse.

Replacing the screw afterwards

Every method except the dedicated removal tool leaves the screw either cosmetically marked, physically modified, or destroyed outright — and a one-way screw that's been drilled, slotted or gripped with pliers no longer does the job it was specced for. If it was doing security work — a number plate, a public fixture, an access panel — replace it with a fresh one-way screw rather than reinstalling the damaged original or swapping in a standard screw. AIMS stocks the full one-way screws range, including Champion one-way screws and the GJ Works One-Way Screw Kit for a mixed-size trade stock — or the broader Security Screws and Security Fasteners ranges if the application calls for a different tamper-resistant head type — Torx security (pin-in-Torx), snake-eye or spanner-head screws are common alternatives worth knowing about, though they need a different removal tool to this guide's.

AIMS supply — selection guide

Removal:

• Champion OWS-RT One Way Screw (Anti-Theft) Removal Tool — the dedicated tool for Method 1, above.
• Screw extractors — for the shank-remains-in-the-hole scenario under Method 4.
• Left-hand drill bits — bites in normally, then backs the remaining shank out anti-clockwise the moment it grips.

Replacement fasteners:

• One Way Screws — the full AIMS range.
• Champion NPS5 M6 x 20 One Way Screw (50/pack) for straightforward replacement.
• GJ Works One-Way Screw Kit (220 pieces) for a mixed-size trade stock.

Wider security fastener range:

• Security Screws and Security Fasteners for Torx security, snake-eye and other tamper-resistant head types.
• Security Nuts & Clips for matching tamper-resistant nuts.

Call (02) 9773 0122 or contact the AIMS team if you need help matching a removal tool or replacement screw to what's already installed.

Frequently Asked Questions

What is a one-way screw?

A one-way screw is a security fastener with a rounded, asymmetrically ramped slot — one side is a steep wall, the other a shallow chamfer. A standard screwdriver bites normally when driving it in clockwise, but cams out (slips) when backed out anti-clockwise, because the blade rides up the ramp instead of gripping it. It's also called a clutch-head screw.

How do you remove a one-way screw without damaging it?

Use a dedicated one-way screw removal tool. It replaces the flat blade with two hardened points sized to the screw's slot, which dig into the ramp under firm downward pressure rather than sliding up it — the only method that gets the screw out without cutting, drilling or gripping it externally.

Can locking pliers remove a one-way screw?

Yes, if the head has enough clearance above the surrounding surface for the jaws to get around its outer diameter. Clamp onto the head itself rather than the slot. If the jaws slip on a smooth or rounded head, filing two flat faces onto opposite sides first gives them something to bite.

Is it OK to drill out a one-way screw?

Only as a last resort. Drilling destroys the screw and risks damaging whatever it's threaded into if the pilot hole isn't dead-centre or goes too deep. Try a dedicated removal tool, locking pliers, or cutting a new slot first — drilling is for a head that's already corroded, rounded or otherwise too damaged to grip any other way.

Do I need to replace a one-way screw after removing it?

If it was doing security work, yes. Every removal method except the dedicated tool leaves the screw cosmetically marked, physically modified, or destroyed — once damaged, it no longer provides reliable resistance to removal. Replace it with a fresh one-way screw rather than reinstalling the original or swapping in a standard screw.

Are one-way screws the same as other security screws?

No — "security screw" covers several different tamper-resistant head designs. One-way (clutch-head) screws use the ramped-slot design this guide covers; Torx security (pin-in-Torx), snake-eye and spanner-head screws use different mechanisms and need their own matching removal tool.