In linear motion, there are few types of components that are truly interchangeable—that is, where a product from one manufacturer is a dimensional and technical replacement with a product from another manufacturer. In fact, only linear ball bearings (bushings) and shafts are commonly interchangeable between manufacturers, with very few dimensional and technical differences. Not only are the assemblies interchangeable, but bearings from one manufacturer can be installed on shafts from another manufacturer. This is because shafts have very simple geometry and are manufactured in a small range of materials and hardness ratings.
Profiled rails and carriages can be interchanged to a certain degree. Because of the rail’s complex geometry, a carriage from one manufacturer cannot be mounted on a rail from a different manufacturer. In fact, carriages and rails of different series or styles from the same manufacturer are often unable to be used interchangeably. With profiled rails and carriages, the best option for an interchange is to find another manufacturer’s product in the same size class (size 15 or 25, for example) that has a similar overall height, width, length, and mounting holes. Then, the technical specifications, including dynamic and static load capacity, preload, and accuracy, must be checked.
To help users navigate this complex landscape of part numbers and technical specifications, several manufacturers have created interchange tables or web-based tools. Below is a roundup of the interchange resources available from linear motion suppliers.
1. Bosch Rexroth offers a comprehensive interchange tool that includes profiled rails, linear bearings (bushings), and roller rails. The tool allows you to start with manufacturer and drill down from there, or to begin directly with the part number. The results include an editable selection criteria table, so you can choose which specifications must be an exact match and which can vary. There are also part number guides for the Bosch Rexroth product and for the competitor’s product, making it easier to form an apples-to-apples comparison.
2. The medias® interchange tool from INA/FAG is based on a keyword search. The database includes roller bearings, so be as specific as possible in order to narrow the list of potential options to just linear bearings or profiled rail products.
3. LM76 provides an interchange chart for its Series A linear bearings in both closed and open versions.
4. In its “Bearing and Linear Reference Guide” (starting on p. 20), NSK publishes interchange tables for its linear guide products. Also included is a part number guide for both the NSK product and the competitor’s product.
5. PBC Linear provides an easy-to-use interchange chart for its Simplicity® linear bearings.
6. Rockford Linear Motion provides a chart for interchanging its profiled rail products with common series from other manufacturers.
7. In its “Profiled Rail Linear Guides” catalog (starting on p. 130), Thomson Linear supplies an interchange chart, including a part number guide for both its products and the competitor’s products.
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