In many linear actuator applications, you may need additional supports to help move your desired object or to protect your linear actuator from uneven loads. Generally, you’ll have two choices of supports you have to pick from; Linear Guides and Drawer Slides. But what is the difference? Why choose one over the other and how do you know which one is best for your application? The goal of this blog is to explain the differences between these two devices and help you decide which one to use for your next project.
Linear Guides
Linear Guides are support mechanisms that are used to carry heavy loads and ensure straight and level linear motion. Linear guides will usually consist of two components; the sliding carriage and the rail. The sliding carriage is the element that moves along the rail and supports the attached load. The design of the sliding carriage and the rail will depend on the style of linear guide. The two most common styles of linear guides are the sliding contact guides and roller bearing guides. Linear guides are designed to allows you to move a significant amount of weight along a single axis with great ease and their load carrying capability allows linear motion without restriction. If you want to learn more about Linear guides, check out our Linear Bearing 101 blog. Linear guides are commonly used in many industrial machines and are often used in CNC machines and 3D printers.
Drawer Slides
A drawer slide is a mechanism that can carry an object and allows for telescopic motion in one axis. Drawer slides generally work by having one drawer member that slides over a cabinet member, which allows the entire mechanism to extend or retract. Generally, you will use a pair of drawer slides in any application and will most likely encounter two main types: Roller Slides and Ball-Bearing Slides, although ball-bearing drawer slides do provide a larger carry load capacity and longer extensions. If you want to learn more about Drawer Slides, you can check out our Drawer Slides 101 blog to learn more. Drawer slides are commonly found in a wide range of household or office applications like desk drawers, kitchen cabinets, and pull out cutting boards but can be used in a wide range of applications that require linear extension and retraction.
What’s the Difference?
Based on the above descriptions, you probably have guessed that one of the biggest differences between linear guides and drawer slides is that drawer slides are telescopic and linear guides are not. Because the sliding carriage slides along the rail, this requires the rail to be as long as the range of the linear guide. While with drawer slides, the drawer member slides over the cabinet member which increases the length of the mechanism and allows for extension. This telescopic ability is why drawer slides are commonly used in cabinets over linear guides but can also be used in industrial and robotic applications, like shown in the video below where the robotic arm uses a pair of drawer slides to allow the arm to collapse and extend.
Another difference between linear guides and drawer slides are that linear guides are designed to handle various types of forces, including uneven and side loading, while drawer slides are not. When you look at the specifications of linear guides, you will often see torque specifications for that linear guide which describes how much the torque the guide can handle due to off center forces. You will also sometimes see linear guides that have different load ratings for compressive and tensile loads. These various force and torque ratings are given because linear guides are design to protect actuating components as well as be used in different orientations. For drawer slides, they are often designed to be used in a single orientation and are not designed to handle sizable torques. Typically, drawer slides are used in either a usual cabinet application, where a pair of drawer slides support a canter lever load that is perpendicular to gravity, or used as guides in pop-up applications, where the slides do not carry a sizable load but are used to stabilize the object. There are drawer slides that are designed to be mounted underneath the load and some that can be both side mounted and bottom mounted, but the load specifications will vary for the different orientation. Because linear guides are designed to handle various types of loads, they are much thicker than drawer slides and require more space to install.
Should I Choose a Drawer Slide or a Linear Guide?
Your choice between whether to use a drawer slide or linear guide is almost completely dependent on your application. The design differences described above makes it clear that certain applications are better suited for linear guides, while others are more appropriate for drawer slides. If your application is similar to a common cabinet application or if you require telescopic motion, then drawer slides maybe the best option for your application. If you require a support to stabilize an actuating component and protect it from uneven loads and torques, then linear guides are a good option for you. There are also many instances where both linear guides and drawer slides may be used and, in this case, you must prioritize the differences between these supports to decide which one is for you. In many projects, you can design your mechanism around what support you prefer and make up for their limitations within other aspects of your design.
