One-Way Security Screws
One-way screws resemble a slotted screw, but the drive uses ramped, angled surfaces rather than a plain straight slot. A properly fitted flat-blade driver can apply installation torque in the tightening direction; turned the other way, the driver tends to ride up the ramps instead of holding engagement. The design suits installations where routine removal isn't expected — removal typically calls for specialized tooling or another planned service method.
How one-way security screws work
The drive has opposing engagement faces cut into the head. On one side, a flat-blade driver seats against a face that lets it apply torque normally, so the screw drives in and tightens as expected.
The reverse sides of those same faces are ramped. When a driver tries to turn the screw counterclockwise, the blade tends to cam or slide up the ramp rather than hold engagement, instead of turning the screw the way a plain slot would.
This discourages casual removal with an ordinary screwdriver and suits installations that don't require routine disassembly. It's tamper-resistant by design, not removal-proof — a planned removal method should be identified in advance if future access may be needed.
- Machine Screws
- Sheet-Metal Screws
- One-Way Removal Tools
Ranges shown represent what we generally offer for this drive. Not every size or configuration is necessarily available at all times. Exact dimensions, availability, minimum quantities, removal tooling, and possible custom configurations should be confirmed when requesting a quote.
How to specify a one-way security screw
A machine screw generally installs into a tapped hole or nut, while a sheet-metal screw forms or engages threads directly in the receiving material. Because the drive is install-only by design, whether the assembly may need future servicing is part of specifying it — not an afterthought. Confirm the following, and include as much as possible on any RFQ:
- Screw formMachine screw or sheet-metal screw
- DiameterNominal screw diameter
- Thread type / pitchMachine thread size or sheet-metal thread type
- LengthOverall or thread length
- Round-head clearanceClearance needed for the round head
- MaterialSteel
- FinishZinc-plated
- Substrate / mating threadWhat the screw threads into or engages
- Installation methodDriver type and access during install
- Future service or removal needsWhether the assembly may need to be reopened later
- QuantityFor stock pricing or a custom production run
- Drawing or printRequired for any custom configuration
This list is a starting point for a quote request, not a substitute for engineering review of your specific application.
Plan installation and removal before ordering
One-way screws normally install with an appropriately sized flat-blade driver — proper blade fit helps apply installation torque without damaging the drive. The ramped geometry intentionally resists ordinary reverse engagement once installed. If future access may be required, review removal tooling and your service plan before installation; specialized removal tools may be available, but suitability depends on the specific fastener and installation. Confirm the intended removal method with Screw & Supply before you order.
Drive Guide →
Compare one-way against our other security drive systems to confirm it fits your job.
Drivers & Kits →
General installation drivers. Confirm separately whether a one-way removal tool is required — not every kit includes one.
Request a Quote →
Tell us your application and any future removal requirements so we can confirm the right setup.
Where install-only fastening is useful
One-way screws are commonly considered where casual removal should be discouraged and routine disassembly isn't expected.
- Transit, Rail & Signage →
Used on signage and equipment tags exposed to public access.
- Machinery Guarding & Panels →
Secures guards and covers not intended for routine removal.
- Public Restrooms & Partitions →
Resists casual tampering with fixtures and partitions in public spaces.
- Detention & Institutional →
Used on fixtures where install-only fastening supports a secure environment.
- Utility & Infrastructure →
Fits outdoor utility fixtures exposed to public access.
- Amusement & Fitness Equipment →
Used on public-use equipment where casual disassembly is undesirable.
Standard configurations and custom specials
We can help identify a standard one-way machine or sheet-metal screw that fits your application, or review requirements for a custom special. For a custom inquiry, provide a drawing or print with diameter, thread requirements, length, material, finish, quantity, application details, substrate, installation method, future removal requirements, and any inspection or documentation requirements. We'll review what you send and follow up on feasibility.
Common questions
- How does a one-way security screw work?
- The drive has opposing engagement faces that a properly fitted flat-blade driver can turn in the installation direction. The reverse sides are ramped, so a driver attempting to turn the screw counterclockwise tends to slide or cam up the ramp instead of maintaining normal engagement.
- Do one-way screws require a special installation tool?
- Installation generally uses a properly sized standard flat-blade driver. Correct blade fit helps apply installation torque without damaging the drive.
- Can a one-way security screw be removed after installation?
- The ramped drive resists ordinary counterclockwise engagement with a standard driver, but it is not impossible to remove. Removal may require specialized tooling or another planned service method, and should be confirmed with Screw & Supply.
- Which one-way screw forms and sizes are available?
- Available forms include machine screws and sheet-metal screws, generally in sizes from #6 through 1/4 inch. Exact availability varies and should be confirmed when requesting a quote.
- What material and finish are offered?
- The verified offering is steel with a zinc-plated finish. Confirm current availability when requesting a quote.
- Does Screw & Supply provide one-way removal tools or review custom requirements?
- One-way removal tools are offered as a category, and we can review custom fastener and removal-tool requirements. Send your details through a quote request and we will follow up.