Sources and scope for this page: Industry convention — no single governing standard (conventional usage, definitions vary between sources), covering the definition of thread rolling. No independent source check is recorded for this page: the content rests on the sources listed and on the working shown on the page. How sources, methods and updates are recorded.
Definition
Rolled threads are formed, not cut, so the grain flow follows the thread profile instead of being severed by it. That makes a rolled thread roughly 20 to 30% stronger in fatigue than a cut one of the same size, and it leaves no chips.
The blank diameter is not the nominal diameter — it is approximately the pitch diameter, because the material has to flow up into the crests. Using nominal-diameter stock produces an oversized thread.
Common misuse
Turning a thread blank to nominal diameter before rolling. It makes the finished thread too large; the blank should be near pitch diameter.