Two-Hole Spanner Security Screws
Two-hole spanner screws use two holes positioned in the head as the drive interface. A matching spanner bit or driver uses two pins or prongs that engage those holes — common flat, Phillips, hex, and ordinary six-lobe drivers don't provide the intended engagement. The matching tool allows normal installation and authorized removal, which is why the drive is used where casual access or removal should be discouraged.
How two-hole spanner security drives work
Two holes in the fastener head form the drive interface. A compatible spanner tool has two pins or prongs sized and spaced to fit into those holes, transferring installation or removal torque through both engagement points at once.
Correct spacing and tool size are necessary for proper engagement — full, even contact at both holes helps reduce slipping and damage to the drive during use.
The drive discourages casual removal with common tools, but it remains tamper-resistant rather than removal-proof. Unlike a one-way screw, a spanner screw is designed for authorized removal with the matching tool, not just one-time installation.
- Machine Screws
- Sheet-Metal Screws
- Spanner Drivers & Bits
Ranges shown represent what we generally offer for this drive. Not every size or head style is necessarily available in every configuration. Exact dimensions, drive size, tool compatibility, availability, minimum quantities, and possible custom requirements should be confirmed with Screw & Supply.
How to specify a two-hole spanner security screw
Machine screws are generally used with a tapped hole or nut, while sheet-metal screws form or engage threads directly in the receiving material. Flat heads are normally selected where a countersunk, flush installation is required; pan and oval heads give different installed profiles. The matching spanner tool must correspond to the hole spacing and drive size, and environmental and compatibility requirements should be reviewed for your specific application. 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
- Head stylePan, flat, or oval
- Spanner-drive sizeMatched to head diameter, #4–#14
- Material18-8 stainless steel
- Substrate / mating threadWhat the screw threads into or engages
- Installation environmentIndoor, outdoor, or exposure conditions
- Matching bit or driverSized to the drive on the screw
- 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.
Match the spanner tool to the fastener
Spanner bits and drivers use two pins or prongs to engage the head — tool size and pin spacing must match the fastener, and a mismatched or poorly seated tool can slip or damage the engagement holes. Order or confirm the necessary tooling with the screws; not every security kit contains every spanner size.
Where controlled access matters
Spanner screws are often considered for public-facing fixtures, equipment panels, and assemblies that must remain serviceable by personnel with the matching tool — including elevators and escalators, where fixtures need to stay accessible to service staff but resist casual public tampering.
- Public Restrooms & Partitions →
Secures fixtures and partitions in high-traffic public spaces.
- Transit, Rail & Signage →
Holds transit fixtures and signage exposed to public contact.
- Detention & Institutional →
Used on institutional hardware requiring controlled access.
- Machinery Guarding & Panels →
Keeps guards and access panels serviceable only with the matching tool.
- Amusement & Fitness Equipment →
Used on public-use equipment where casual tampering is a concern.
- Utility & Infrastructure →
Fits utility enclosures and fixtures that need periodic authorized service.
Standard configurations and custom specials
We can help identify a standard spanner configuration 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, head style, drive details, material requirements, quantity, application details, installation environment, matching tool requirements, and any inspection or documentation requirements. We'll review what you send and follow up on feasibility.
Common questions
- What is a two-hole spanner security screw?
- It's a security screw with two holes in the head that form the drive interface, engaged by a matching spanner tool with two pins or prongs sized to fit those holes.
- Can an ordinary screwdriver remove a spanner screw?
- No. Flat, Phillips, hex, and ordinary six-lobe drivers do not engage the two-hole drive. Normal installation and authorized removal require a matching spanner bit or driver.
- How do I select the correct spanner bit or driver?
- The tool's pin spacing and size must match the fastener's drive. A mismatched or poorly seated tool can slip or damage the engagement holes, so confirm sizing before ordering.
- Which screw forms, head styles, and sizes are available?
- Available forms include machine screws and sheet-metal screws, generally in pan, flat, and oval head styles, in sizes from #4 through 1/4 inch. Exact availability varies and should be confirmed when requesting a quote.
- What material is offered for spanner security screws?
- The verified material is 18-8 stainless steel. Confirm current availability when requesting a quote.
- Can Screw & Supply provide matching tools or review custom requirements?
- Yes. We can help confirm matching spanner bits and drivers, and review custom fastener requirements. Send your details through a quote request and we will follow up.