Inside the Cold Header: How a Screw Is Born in One Stroke
Every catalog screw began as a coil of wire and a single hammer stroke. Cold heading is the most productive metal-forming process in industry — and its physics explain fastener quality.
The stroke, frame by frame
Wire feeds to a stop, gets cut to length, clamped in a die, then struck by punches that upset the material into the head geometry — one stroke, one blank, at 100–300 per minute. Transfer fingers move the blank through stations: preform, final head, and sometimes point forming, all within the same machine cycle.
Why the process defines quality
- Grain flow follows the head contour continuously — the fatigue advantage no machining reproduces.
- Work hardening strengthens the surface exactly where stress concentrates.
- Die wear is the quiet enemy: a worn die drifts head dimensions micron by micron, which is why SPC charts track headed blanks, not just finished screws.
Material matters before the machine
Cold-heading grades of wire (specified for ductility and surface quality) head cleanly; wrong grades crack. Topprecision sources certified heading wire, monitors die condition through SPC, and produces blanks whose grain structure — visible in sectioned samples — is the reason our cold-headed aluminum bolts outperform machined equivalents.
