Custom Combination Screw Manufacturer. TYF (Guangdong Taiyuanfeng Metal Products Co., Ltd.) manufactures custom and non-standard combination screw to your drawings, samples and application requirements. Combination (SEMS) screws with captive washers for faster assembly.Most parts are formed in-house by cold heading and closed-die forming, then thread-rolled and inspected. Materials: carbon steel and alloy steel, stainless steel (304/316), brass and copper alloy, aluminum and zinc alloy. Surface finishes are selected per drawing and application; coating thickness (Zn/Ni/Cu) and salt-spray corrosion resistance are verified with in-house inspection.Certified to IATF 16949:2016, ISO 9001:2015 and ISO 14001:2015. Send your drawing for a quote.Request a Quote / Upload Your Drawing