How To Mount Parallel Rails: Getting Started

When mounting linear systems, the rail will conform to the mounting surface. For installations with multiple parallel rails, the mounting surfaces must be accurate and the rails properly aligned to avoid binding, misalignment or other issues that degrade system performance. Achieving the highest accuracy therefore requires a sufficiently flat mounting surface and a straight shoulder.

However, successfully mounting parallel rails is often easier said than done, especially if you're not prepared for the level of precision the installation requires. This blog post, the first in a series on parallel rail installation, covers the preparations and the tools you'll need to complete the job effectively.

Before You Begin, Take Care of the Essentials

Regardless of your expertise and resources, you'll need to perform these essential tasks before beginning the installation.

1. Make sure the reference bed and rail are clean and dry. Remove all burrs and surface blemishes from the machine or device where the linear guide will be mounted. Wipe the surfaces with a clean cloth.

2. Clean the linear guide. Use a clean cloth to remove any dust or rust-preventive oils from the guide.

3. Consult manufacturer information. Keep in mind that the mounting surface has to be sufficiently rigid on its own to avoid deformation under the load. Flatness is especially critical when mounting multiple rails in parallel, because vertical alignment is more challenging than horizontal alignment. Motion component specialists like IKO publish tables in their catalogs, showing the recommended tolerances for height deviation and parallelism, which can vary accuracy class.

To Install Parallel Rails, Select These Tools

Under ideal circumstances, you'll have a full complement of tools to do the job. If you do not, workarounds are possible. With that in mind, we suggest having the following on hand:

• Dial indicator to find parallelism errors. Resolutions of 2 µm or finer are appropriate for high-precision installations.

• A calibrated torque wrench which tightens the rail bolts to a manufacturer's torque values to ensure proper holding downforce.

• Clamps to hold down the rails during installation.

• Plus a straight edge, feeler gauges, honing stone and clean cloth.

Now that you've prepared for installation, you'll want to read Part 2 of our series. That post presents two methods for accurately mounting parallel rails, and shows how you can achieve a successful installation without a machined reference surface or extensive prior experience.

For more information, download our white paper.