Brands

Get to Know SDP/SI and the Other Designatronics Brands
We manufacture and supply precision gears, superior mechanical components and customized power transmission and motion control solutions to aerospace, medical, defense, and robotics industries. Explore the many products, engineering and manufacturing capabilities and services provided by SDP/SI, Quality Bearings & Components, and QTC Metric Gears here.


Since 1950, design engineers have depended on SDP/SI for high-quality components, subassemblies, and engineering expertise. As a company founded and managed by engineers we understand and respond to the developing needs of our customers better than anyone.

When a standard product won't meet your requirements we can provide alternative solutions through custom design and manufacturing. Our engineering and manufacturing teams will partner with you throughout the entire process. By providing design, development, manufacturing, assembly, and testing in one location, we can ensure the end product will meet your expectations.


QBC is an authorized distributor and supplier of some of the world's largest bearing and linear motion component manufacturers. QBC is considered "The Bearing Marketplace", since they are the one-stop shop for all your bearing needs.

We offer ball and roller bearings, linear bearings, spherical bearings, shafting, mounting blocks, and thrust bearings ranging from commercial to ultra-precision quality. We offer custom-made bearings for your specific application and unique environments as well as value-added services including JIT deliveries, blanket orders, special packaging, bearing re-lubing services, and engineering support.


In North America, QTC METRIC GEARS is your complete source for metric gears and gear products, used in industrial applications. With over 20,000 standard item configurations, we can meet the ever-increasing need for metric gears in both replacement and OEM applications.

Through modular manufacturing, QTC Metric Gears can offer a broad range of sizes, configurations, and materials at shorter lead times for special applications.