Product Description
No.12 A2 Stainless Steel Countersunk Torx Self-Tapping Screws
No.12 countersunk self-tapping screws manufactured from A2 stainless steel and fitted with an internal six-lobe Torx-style drive. The countersunk head is designed to sit flush with the surface when installed into a correctly prepared countersink.
The No.12 thread has an approximate outside diameter of 5.5mm. These screws are available in imperial lengths from 1/2" to 2" and in pack quantities from 1 to 1,000.
Key Features
- No.12 self-tapping screw thread
- Approximately 5.5mm outside thread diameter
- A2 stainless steel construction
- Good general-purpose corrosion resistance
- Flush-fitting countersunk head
- Internal six-lobe Torx-style drive
- Positive driver engagement with reduced cam-out
- Available in lengths from 1/2" to 2"
- Available in packs from 1 to 1,000
Available Lengths
| Screw Size | Nominal Diameter | Imperial Length | Approximate Metric Length |
|---|---|---|---|
| No.12 | 5.5mm | 1/2" | 13mm |
| No.12 | 5.5mm | 5/8" | 16mm |
| No.12 | 5.5mm | 1" | 25mm |
| No.12 | 5.5mm | 1 1/4" | 32mm |
| No.12 | 5.5mm | 1 1/2" | 38mm |
| No.12 | 5.5mm | 1 3/4" | 45mm |
| No.12 | 5.5mm | 2" | 50mm |
Countersunk screw length is measured from the top of the head to the end of the point.
Product Dimensions
| Nominal Size | No.12 |
|---|---|
| Outside Thread Diameter | Approximately 5.5mm |
| Reference Thread Pitch | Approximately 1.8mm |
| Head Diameter | Approximately 10.6mm |
| Head Diameter in Inches | Approximately 27/64" |
| Head Type | Countersunk |
| Drive Type | Internal six-lobe Torx style |
| Material | A2 stainless steel |
Torx-Style Drive
The internal six-lobe recess provides positive contact between the screw and driver bit. This can reduce driver slippage and cam-out compared with conventional cross-recessed screws, particularly during repeated installation.
Use a correctly fitting Torx-style driver bit and keep the tool aligned with the screw. The precise drive size should be confirmed against the supplied product before selecting installation tooling.
Standards Information
ISO 14586 is the specific international standard covering hexalobular socket countersunk head tapping screws in sizes from ST2.9 to ST6.3. No.12 corresponds approximately to the ST5.5 diameter covered by this standard.
DIN 7982 is a withdrawn standard for cross-recessed countersunk self-tapping screws and is not an exact drive-standard reference for a Torx-style product. It may be used commercially to describe a comparable countersunk head and tapping-thread form, but full DIN or ISO conformity should not be stated unless confirmed by the manufacturer.
A2 Stainless Steel
A2 stainless steel provides good resistance to corrosion in many indoor, outdoor and general industrial environments. It is suitable where improved corrosion resistance is required without applying a separate protective coating.
A2 stainless steel is not normally the first choice for prolonged exposure to seawater, coastal salt spray or strongly chloride-contaminated environments. A4 stainless steel should be considered for those conditions.
Typical Applications
- Sheet-metal fabrication
- Equipment panels and enclosures
- Vehicle bodywork and interior fittings
- Heating and ventilation equipment
- Electrical and electronic housings
- General engineering assemblies
- Plastic components suitable for self-tapping screws
- Outdoor fixtures in moderately corrosive environments
Installation Advice
These are self-tapping screws rather than self-drilling screws. A correctly sized pilot hole will normally be required. The appropriate pilot-hole diameter depends on the material, its thickness and the amount of thread engagement required.
Prepare a suitable countersink if the head must finish flush with the surface. Use a matching driver bit, maintain alignment and avoid excessive installation speed or tightening torque.
Stainless steel threads can gall or seize. Where removal may be required, consider using a suitable anti-galling lubricant and install the screws at a controlled speed.
Useful Links
- View all countersunk Torx self-tapping screws
- View all self-tapping screws
- No.6 A2 stainless countersunk Torx self-tapping screws
- No.8 A2 stainless countersunk Torx self-tapping screws
- No.10 A2 stainless countersunk Torx self-tapping screws
- No.12 A2 stainless pan-head Torx self-tapping screws
- How to measure a bolt or screw
- Fastener materials and technical guide
Specifications are intended as a guide. Confirm the drive size, head dimensions, material certification and standard compliance before use in safety-critical or specification-controlled applications.
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