Carriage bolt square-neck insert die

* Specialized square-neck cavity – accurately forms the square anti-rotation shoulder under the round head, ensuring proper bolt seating. * High-strength powder metallurgy steel + TiAlN coating – resists severe impact and abrasive wear when forming carbon/stainless steels. * Tight square dimension tolerance (±0.03 mm) – guarantees consistent neck width and depth, eliminating secondary milling or broaching. * Optimized fillet radius at square-to-shank transition – minimizes stress concentration, prevents root cracking under high heading loads. * Mirror-polished cavity surfaces – reduces galling and sticking, enables smooth part ejection and bright finish on the square section. * Quick-swap insert design – replaceable without disassembling the die holder, cutting changeover time by 50%. * Proven at multi-station headers up to 200 spm – stable performance, scrap rate <0.4% over long production runs. * Customizable square size and head diameter – adaptable to bolt sizes M6–M20 and various standard lengths. * Optional DLC coating – extends insert life 2-3× in highly abrasive conditions (e.g., high-silicon or high-strength alloys). * 100% dimensional inspection – each insert CMM-verified for squareness, concentricity, and hardness (HRC 58–62); fully interchangeable.