About us

Ningbo DEMY (D & M) Bearing Co., Ltd is one of the leading manufacturers of ball bearings, roller bearings, and many other bearings, in China. We also export chains, belts, hardware & spare parts, as well as auto parts, and more.

Main products
Bearings, chains, belts, hardware, spare parts, auto parts, sprockets and gears, etc. are all produced at DEMY.
We now produce bearings of over 12,000 different kinds. They can be classified into 9 types and 5 precision classes based on international standards, Chinese national standards, and customers' requirements. The bearing ID ranges from 5mm to 6300mm. Our ball bearings, roller bearings, and auto bearings are our most popular bearing products.
We also provide driving chains, conveyor chains, roller chains, which usually run over sprockets, and leaf chains which run over sheaves.
DEMY belts and chains have similar functions, which is to transmit power. Conveyor belts, synchronous belts, automotive timing belts, and V-belts are all available here.
Our products are used in over 60 industries, including railway, automobile, metallurgical, petro-chemical, military, etc.
For more detailed product information, please refer to our product page.
Manufacturing process- our guarantee of product quality
When we started DEMY, we were determined to provide high-precision, good-wearing, tear-resistant bearings, chains and belts to all our customers. We've achieved this goal through the use of experienced technicians, advanced production equipment, and complete quality management systems.
For example, in our standard ball bearing and roller bearing manufacturing factories, we first start with high-quality raw materials (mainly steels) for each component of a bearing. During the manufacturing process, we give much attention to every component's processing, especially the four primary parts of a standard ball bearing or roller bearing: the outer race, the inner race, the steel balls (rolling balls), and the bearing cage. We not only have strict limitations on their sizes, but we also utilize precise machine tools and cutting machines to produce and process them. We then have independent post-process workshops, vibration-measuring workshops, cleaning workshops, and packaging workshops to further process our ball bearings and roller bearings. Thus, DEMY bearings are certain to be high quality.
We also apply similar manufacturing processes to our other products: chains, belts, auto parts, etc.

Future plan
DEMY products, which are ISO9001:2000 certified, are widely used in North and South America, South-east Asia, Europe, the Middle East, and more.
In the future, we will expand to even more international markets. In order to achieve this goal, we have established a thorough after-sales system of service, to ensure the complete satisfaction of each client.