Setting Ideas into Motion SDP/SI - Stock Drive Products/Sterling Instrument provides mechanical components, engineering and manufacturing services for industrial and commercial applications. Providing Component Choices and Design Solutions Since 1950 Design engineers depend 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. Over 87,000 inch and metric dimensioned components are available for fast turnaround. 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 engineering, manufacturing, assembly, 3D printing and testing in one location we can ensure the end product will meet your expectations. AS9100 Registered.