Double-ended Screws

Double-ended screws, also known as studs or threaded rods, are specialized machine-thread fasteners with precision machine threads on both ends and a smooth shank in the center. Their key advantages include bidirectional connection, adjustable spacing, and high-strength linkage. Manufactured in compliance with ISO 8676, both ends feature symmetrically rolled threads with 6g-grade precision, and thread lengths can be customized as required. The central shank is precision-ground to ensure straightness, with an error of ≤0.02 mm/m, and the transition between the shank and threads is smoothly rounded to reduce stress concentration. With a tensile strength of grade 8.8 or higher, double-ended screws are ideally suited for applications requiring the connection of two separate components with adjustable spacing.

Products are widely used in bridge engineering, mechanical equipment linkages, building steel structures, automotive engines, and mold assembly. In bridge construction, they connect bearing supports to beams, with the bidirectional threads ensuring secure connections under load. In machinery applications, they link motors to bases or reducers to frames, where adjustable spacing simplifies installation and alignment. In steel structures, they join beams and columns, with their high strength ensuring structural stability. In automotive engines, they fasten cylinder heads to engine blocks, meeting the high-temperature and high-strength requirements of engine operation. In mold manufacturing, they secure plates to bases, improving mold accuracy. Double-ended screws are therefore key connecting components for multi-part assemblies.

These studs are manufactured from high-strength materials such as alloy steels 35CrMo and 40Cr, carbon steel 1045A, and stainless steel 316. Alloy steel versions are heat-treated to achieve strength grades of 10.9 or 12.9, with grade 12.9 offering a tensile strength of ≥1200 MPa. Carbon steel meets the 8.8 strength grade for general applications, while stainless steel 316 provides excellent corrosion resistance and high-temperature performance for harsh environments. Surface treatments include black oxide (GB/T 15519), zinc plating (ASTM B633), and chrome plating (ASTM B456), with salt spray resistance ranging from 72 to 144 hours. Certified to ISO 9001 and GB/T 1231 (for high-strength structural fasteners), product deliver reliable performance. Custom options are available for special sizes, different thread pitches on each end, extra-long lengths (up to 500 mm), and special coatings. Packaged in quantities of 50–100 pieces with thread protection to prevent damage and supplied with tensile test reports, they ensure that required connection strength is fully met.