Seamless Screw

The Seamless Screw is made from a solid bar, with no weld lines on its surface. This ensures uniform strength along its entire length. It is ideal for long-distance threaded connections, such as car seat adjuster rods, building tie rods, machine lead screws, and exercise equipment rods. One client used it for electric seat rails, requiring high precision and excellent wear resistance. We produced the Seamless Screw using cold-drawn bars and thread rolling. The surface hardness reached HV500+. After 100,000 slide tests, wear was less than 0.05 mm. Today, this screw is used in three of their car seat models.

Diameters range from φ2 to 10 mm, with lengths from 4 to 50 mm. Materials include 10B21, 35#, 45# steel, SUS304, and SUS430. Surface finishes include zinc, nickel, chrome, Dacromet, phosphate, passivation, and black oxide. Thread types include coarse or fine standard threads, and non-standard pitches are also available. Thread precision is 6g, and straightness is 0.02 mm per 100 mm. Hardness can be heat-treated to HRC 22–32 or HRC 32–39. We use ultrasonic cleaning to remove oil and chips, and an optical sorter checks for complete threads. Before packing, thread ring gauges are used for spot checks-go gauges must pass, and no-go gauges must fail. Salt spray resistance: regular zinc plating lasts 48+ hours; Dacromet plating lasts 96+ hours.

Non-standard lengths can be made up to 50 mm, and longer lengths can be discussed. Applications include motorcycle connecting rods and building tie rods. To prevent bending during shipping, we use straight tube packs or PVC tube packs. For large diameters, screws are laid flat on pallets; for small diameters, paper tubes with anti-rust paper are used. This ensures no bending and no rust. Our monthly production capacity is high, and we supply SAIC, FAW, Dongfeng, GAC, Great Wall, Geely, and Chery, earning multiple supplier awards.