Self-Tapping Screw
Characteristics
● Self-threading — cuts/forms its own mating thread as driven in; no pre-tapped hole or nut needed.
● Fast, low-cost assembly — fewer process steps than machine screws.
● Strong holding power — coarse pitch gives high pull-out and strip resistance in thin materials.
● Versatile — available in many head (pan, countersunk, hex), drive (PH, PZ, Torx) and point (sharp, blunt, drill) styles.
● Flush finish option — countersunk heads seat flush for a smooth, snag-free surface.
● Corrosion options — stainless (A2/A4) and protective coatings for indoor to harsh environments.
Uses
● Sheet-metal & HVAC/ducting — quick joining of thin steel/aluminium without nuts.
● Appliances & electrical enclosures — flush countersunk heads for safe surfaces.
● Automotive interiors & trim — lightweight, vibration-resistant fixing (often stainless).
● Electronics & control cabinets — clean finish, easy field service.
● Furniture, plastics & wood — coarse thread engages rigid plastic/plywood well.
● Construction & roofing — self-drilling types fix steel decking fast.
Standards Quick Reference
|
Standard |
Type |
Notes |
|
DIN 7981 / ISO 7049 |
Pan head self-tapping |
Raised head, general use |
|
DIN 7982 / ISO 7050 |
Countersunk head self-tapping |
Flush finish |
|
DIN 7983 / ISO 7051 |
Raised countersunk head |
Countersunk look with small bearing face |
|
DIN 7504 |
Self-drilling screw |
Drill point, no pilot hole needed |
|
ASME B18.6.4 |
Tapping screws (general) |
North American specification |
Selection Guide
| Requirement | Recommendation |
| Surface must be flush | DIN 7982 countersunk (this standard) |
| Slightly proud head acceptable / higher torque | DIN 7981 pan head |
| Some bearing face but countersunk look | DIN 7983 raised countersunk head |
| Limited back clearance / anti-puncture | Form F flat blunt point |
| Maximum anti-cam-out torque | Type Z (PZ Pozidriv) recess |
| Stainless corrosion resistance | A2 / A4 |
| International generic part | Procure ISO 7050 (= DIN 7982) |