Cold Heading Die Precision: What Can You Expect?

Precision is the single most critical performance metric for a cold heading die. A die that drifts by even 0.02 mm can produce out-of-spec fasteners, triggering customer rejections and production stops. Here’s how precision is measured, controlled and specified in our factory.

Key Precision Metrics

Two measurements define die quality:

• Inner Diameter (ID) Precision — the accuracy of the bore that forms the fastener shank or thread. This directly determines the finished part dimension.
• Concentricity — how centered the bore is relative to the die’s outer reference axis. Poor concentricity causes asymmetric wall thickness, uneven wear and ultimately premature die failure.

Our Precision Standard

BENC MOULD controls both inner diameter and concentricity within 0.01 mm. This is achieved through a combination of precision CNC grinding, wire-cut EDM finishing, and 100% inspection using high-precision projectors and concentricity testers. Every die is individually measured before shipment.

Understanding G4–G9 Precision Grades

Precision grades are defined by the tolerance band on the die’s forming dimension:

What This Means for You

When you specify G6 grade for a screw die, you’re asking for ±0.01 mm on the forming dimension. At BENC MOULD, our standard production tolerance is G6 or tighter. For applications requiring G4–G5, we use dedicated finishing processes and 100% inspection with video measuring instruments to guarantee every die meets spec.