Originally, we used the customer's sample drawings to produce self-locking nuts. The self-locking nuts used by customers were locked with nylon rings. However, the nylon rings will age over time, and the service life of nylon rings in high-temperature areas will be greatly shortened, and the locking effect will deteriorate. We proposed that the above problems can be solved by changing the nylon ring inserts to metal inserts. By changing the process and purchasing new riveting equipment, we use metal lock pieces instead of nylon rings. Customers reported that this change improved the locking effect of the nut and greatly improved the reliability of the product.