Key specifications
| Sizes | ST2.9, ST3.5, ST4.2, ST4.8, ST5.5, ST6.3 |
|---|---|
| Lengths | About 9.5 mm to 50 mm |
| Heads | Pan (ISO 15481), wafer / truss, modified truss |
| Drives | Cross recess (Phillips), square or Torx on request |
| Materials | Case-hardened carbon steel; stainless on request |
| Finishes | Zinc plated, black phosphate, zinc-nickel, ceramic-type coatings |
Made to order in China and shipped FOB or CIF from Tianjin, Ningbo, Shanghai or Shenzhen. Sizes, grades and finishes outside this list can be quoted.
Dimension drawing
ISO 15481 dimensions and drilling range
| Size | Head Ø dk max (mm) | Head height k max (mm) | Recess no. | Drilling range (mm) | Inquiry |
|---|---|---|---|---|---|
| ST2.9 | 5.6 | 2.4 | 1 | 0.7–1.9 | Quote this size |
| ST3.5 | 7.0 | 2.6 | 2 | 0.7–2.25 | Quote this size |
| ST4.2 | 8.0 | 3.1 | 2 | 1.75–3 | Quote this size |
| ST4.8 | 9.5 | 3.7 | 2 | 1.75–4.4 | Quote this size |
| ST5.5 | 11.0 | 4.0 | 3 | 1.75–5.25 | Quote this size |
| ST6.3 | 12.0 | 4.6 | 3 | 2–6 | Quote this size |
Pan vs wafer head
| Head | Best for | Watch point |
|---|---|---|
| Pan | Sheet-to-sheet, brackets, HVAC duct, electrical enclosures | Head stands proud of the surface |
| Wafer / truss | Light steel framing, plasterboard track, thin sheet | Head shape is not standardised; send a drawing or sample |
- For drywall to steel stud, bugle-head drywall screws are a separate product; tell us if you need them alongside framing screws.
Packing, shipping and documents
| MOQ | 500 pcs per specification; mixed sizes can be combined on one order |
|---|---|
| Lead time | 10–15 days for stock items, 25–30 days for production orders, confirmed in the quotation |
| Export packing | Inner boxes or bags labelled by size, export cartons, then palletized and stretch-wrapped; buyer labels and barcodes on request |
| Shipping ports | Tianjin, Ningbo, Shanghai, Shenzhen |
| Incoterms | EXW, FOB, CFR, CIF, DAP, DDP on request |
| HS code reference | HS 7318.14 (self-tapping screws) is the usual heading for self-drilling screws. Confirm the final code with your customs broker. |
| Certificate of origin | ACFTA Form E available on request for buyers in ASEAN countries such as Malaysia, Indonesia, Vietnam and the Philippines |
| Order documents | Commercial invoice, packing list and inspection records agreed in the quotation |
What to include in your RFQ
- Head (pan / wafer) and drive
- Size and length, e.g. ST4.2 × 16
- Steel thickness to drill
- Coating
- Packing, quantity per size, destination
Frequently asked questions
What is the difference between pan head and wafer head screws?
A wafer (truss) head is larger in diameter and lower than a pan head, so it clamps thin sheet better and sits flatter. Pan heads are the standard general-purpose choice.
Which size for joining two 0.8 mm steel sheets?
ST3.5 or ST4.2. The total thickness is 1.6 mm plus any gap, within the ISO 15481 drilling range of both sizes.
What replaced DIN 7504 for pan head screws?
ISO 15481 covers cross-recessed pan head self-drilling screws and replaced the earlier DIN 7504 form.
What is the MOQ?
Reference MOQ is 500 pcs per specification. Standard sizes typically ship in 10–15 days and made-to-order sizes in 25–30 days, confirmed with each quotation. We reply to every RFQ within 2 working hours.
Sources for technical review