304 / 316 · Upper support and lower fastening threads
Stainless Steel Hex Head Sandwich Panel Screws
An upper support thread holds the outer skin of an insulated panel while the lower thread fixes into the support. The hex head and bonded EPDM washer complete a fastening arrangement for roof and wall panels, with solid stainless and bi-metal constructions listed.
- Solid 304 / 316 and bi-metal construction options
- Upper retaining thread supports the outer panel skin
- Pre-assembled stainless steel / EPDM washer
KEY FEATURES & PERFORMANCE
Support the skin.
Secure the panel.
Sandwich panels place the outer sheet and underlying frame at different levels. Two thread zones address those roles: the upper thread supports the outer skin, while the lower thread anchors the fixing. Panel thickness and support conditions set the configuration.
- 01
Upper support thread
The larger thread beneath the hex head engages the outer metal skin. Its position supports the face sheet and helps limit dimpling and core compression when the screw matches the panel build-up.
- 02
Lower fastening thread
The lower thread establishes engagement into the steel or timber support. Its length and position are selected with the panel thickness and support material, rather than inferred from overall screw length alone.
- 03
Solid and bi-metal options
The range lists solid 304 / 316 and bi-metal versions. Bi-metal designs add a welded, heat-treated alloy steel cutting tip; these constructions are separate choices with different support requirements.
- 04
Pre-assembled sealing washer
A broad stainless steel backing disc supports vulcanized EPDM. Correct seating and compression create the weather-sealing contact at the panel face without relying on excessive tightening.
- 05
Hex-head seating control
The external hex flange accepts a matching socket for torque transfer. Tool fit and an agreed stopping position help seat the washer while protecting the outer skin and insulation core.
- 06
Point selected for the support
Self-drilling points and bi-metal Tek 3 / Tek 5 options are listed. The exact point and tested drilling capacity are selected for the support; point numbers alone do not establish a thickness rating.
TECHNICAL SPECIFICATIONS
Size & Configuration Overview
The listed product and series details guide selection of an order configuration.
| Body material | 304 / 316 stainless steel |
|---|---|
| Construction options | Solid stainless steel or bi-metal with welded hardened alloy steel tip |
| Head / drive | Hex washer head / external hex socket |
| Sealing assembly | Pre-assembled stainless steel backing washer with vulcanized EPDM |
| Thread arrangement | Upper support thread and lower fastening thread |
| Point options | Self-drilling point; bi-metal Tek 3 / Tek 5 options |
| Listed diameters | #8, #10, #12 and #14 |
| Listed length range | 1/2-8 in (approximately 13-203 mm) |
| Listed panel cores | PIR, PUR, EPS and rock wool |
| Optional finish | Ruspert coating by configuration enquiry |
Published ranges are not a stock matrix. Grade, size, point, head, thread and finish are agreed in the quotation. A2 / A4 are source shorthand for 304 / 316 families; the ordered grade is defined by its material specification.
APPLICATIONS & CONNECTION PLANNING
Connections & Selection Details
Insulated roof panels
PIR, PUR, EPS and rock-wool panels require the upper support thread to align with the outer skin. Panel profile, core thickness and roof support establish the required length and thread positions.
Wall panels & cold stores
Wall cladding and cold-storage panels are listed applications. The panel supplier’s joint, sealing and movement requirements remain part of the fixing detail; the screw alone does not establish air-tightness or fire performance.
Steel or timber supports
Steel purlins and timber substructures require different point and engagement choices. Specify support material, thickness or timber species, and the full panel build-up when selecting solid or bi-metal construction.
Use the fixing schedule and data for the selected fastener and joint. Published applications do not establish a rated load or universal installation method.
COATING SOLUTIONS
Finish for the
Panel Environment
Ruspert is listed as an optional coating. Its use is reviewed with the selected stainless steel or bi-metal construction, head colour and surrounding panel materials.
Panel skins, support metals and the drill tip may create different corrosion conditions within one fixing. Include the exposure, insulation system, contact materials and requested colour in the coating brief. Test documentation and finish scope are agreed for the actual configuration.
Explore Coating Solutions →CUSTOMER QUESTIONS
Product, OEM & Packaging Q&A
Product selection, custom production and packing details for this screw design.
Product
What does the upper thread support?
It engages the outer metal skin near the head while the lower thread anchors into the support. The spacing must match the panel build-up to help limit face-sheet dimpling and core compression.
Product
How do solid and bi-metal versions differ?
The range lists solid 304 / 316 stainless steel and bi-metal versions with a welded, heat-treated alloy steel drill tip. Select the construction and point against the actual support material and thickness.
Product
Does a Tek number guarantee drilling capacity?
No. A capacity needs the exact screw, point geometry, steel grade, thickness and installation conditions. The quotation should identify the selected configuration and supporting data.
OEM
Can you customise the head, drive and dimensions?
We can review head logos, head shapes, drive details, dimensions and tolerances against your drawing or specified ASME reference. The agreed design defines the production requirement.
OEM
Can you match a colour or surface treatment?
Head colour matching, passivation and specialty finishes can be reviewed for the selected material and application. Provide the colour reference and exposure conditions with your brief.
OEM
Are samples available before production?
Custom samples and initial inspection reports can be arranged before full production. The sample quantity, inspection scope and approval criteria are agreed during development.
Packaging
Which packing formats can we choose?
Small polybags, inner boxes and industrial bulk packing are available formats. Specify the quantity per pack and handling requirements so the packing specification can be agreed.
Packaging
Can inner and outer packs carry our brand?
Yes. Inner and outer box designs, printed logos and brand artwork can be prepared from your supplied files. Artwork and pack dimensions are reviewed before production.
Packaging
Can you include our barcodes and shipping marks?
Private labels, UPC / EAN barcodes, part numbers and shipping marks can be included in the packaging brief. Supply the required data and label layout for checking.
ORDER SUPPORT
Documents, Production & Delivery
Material & inspection records
Material test reports and mill certificates can be requested for the order. Agree the required documents, inspection scope and batch traceability against the selected material before production.
Stock & custom production
Available stock and factory production follow different order routes. Stock availability is checked for the requested configuration; bulk and custom orders are scheduled to the agreed specification and quantity. Timing is established in the quotation.
International shipping
FOB, CIF and DDP arrangements can be discussed for the destination. Shipment tracking supports the agreed transport route. Route availability, DDP coverage and delivery terms are established with the order.
Standards & Material References
| Dimensional references | ASME B18.6.3 / ASME B18.2.1 / ANSI |
|---|---|
| Material / physical references | ASTM F593 (Group 1: 304/305; Group 2: 316) / ASTM A240 |
Confirm the edition, component scope and inspection documents. ANSI needs a specific reference; ASTM F593 group references do not add 305 as a sale option or certify the complete screw.
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