website:https://www.jhmindustry.com/
Shanghai Jian & Mei Industry and Trade Co., Ltd. is the company which manufacture and export fasteners and metal hardware, founded in 2006, with import-export authority. Now, 80% products export to all over the world and 20% sell in domestic market.
https://flyingrc.net/tightnutsbolts.html
The full story has more details and links to my fastener supplier