What is a drawer slide and how do I choose the right one?

A good drawer slide means the difference of years of headaches versus years of convenience. But what goes into a good drawer slide and how do you figure the right one for your need? Here’s a brief guide to help you understand the basics of a drawer slide and how to choose the right one for your application.

THE BASICS

A simple drawer slide has two members: a drawer (inner) member that attaches to the side of a drawer box, and a cabinet (outer) member that attaches to the cabinet’s inner wall surface, within the drawer opening.  Only one of the slide members (drawer) moves when opening a drawer.

A more complex slide structure will include three members, with an intermediate member located between the cabinet and drawer members. Only the drawer and intermediate members move; while the cabinet member remains fixed to its location within the cabinet structure.

Additionally, slides can come in two arrangements: side mount (Picture A) and undermount (Picture B). An undermount slide, mounts in a position that allows a specially designed drawer to sit on top of the suspension, unlike a side mount slide. An undermount slide is often used where it’s desirable to conceal the drawer slide components from view.

Ball bearing drawer slides are also known as rails, runners, and sliders, but they are not the same as glides. A glide uses thin rails on both mounting surfaces, and include plastic wheels on the drawer side allowing movement. Glides are often found on discount furniture; while inexpensive, their movement is much less smooth and the rails are prone to misalignment.

LENGTHS AND EXTENSIONS 

Slides come in many lengths, from as little as 6 in. to as long as 60 in. Length refers to the total length of the slide assembly, when collapsed in the closed position.

How far a slide extends or moves, is called extension or travel. A simple slide that uses just two members, an inner and an outer, generally provides ¾ (or partial) travel. That means the moving drawer member travels at ¾, or 75%, of the slide’s length.  These types of slides are common in residential uses, such as in kitchen cabinetry, or in office furniture, where direct full access to the drawer’s contents is not desired.

Three-member slides have two moving components, the drawer and intermediate members.  In combination, these members tend to extend either the full (100%) length of the drawer slide assembly or even beyond that. Those that exceed the length are called “over-travel” slides because they travel over 100% of the length of the drawer slide assembly. Full-extension slides, are useful if you need easy access to contents.

Pictured above: Top drawer is an example of a full extension slide vs the bottom drawer showing a 3/4 extension drawer slide. 

LOAD CAPACITIES

Determine how much weight your application is likely to see when in use.  Slides’ load capacities fall into three ranges: light-, medium-, and heavy-duty. A light-duty slide, handles loads up to 75 lbs. Light-duty applications often include kitchen and office drawers. A medium-duty slide handles loads between 100 lbs and 150 lbs.  Heavy-duty drawer slides more typically have load ranges over 150 lbs and depending on the application can reach even over 1,000 lbs.

Pictured above: (left) light duty, (center) medium duty, (right) heavy duty 

LOCKS AND DETENTS

Do you want your drawer to be secured in position? In that case, you may want your slide to include a detent or a locking feature.  There are two types of drawer slide detents: detent-in and detent-out.

A detent-in slide has an engagement feature formed on the drawer member and a rubber-like molding secured at the rear of the cabinet member. These two features cooperate to frictionally hold a closed drawer in that position, preventing the drawer from drifting open. You can overcome the detent with a pull on the drawer when opening.

A detent-out slide includes cooperating components that holds the slide in the fully extended position, until you are ready to retract the drawer or a working platform, such as a keyboard tray.  Deactivating a detent-out slide requires a simple “bump” of the extended unit to release the engagement features before pushing it back inside the cabinet.

There are two types of drawer slide locking features: lock-in or lock-out.  Both features include a latching mechanism that secures a drawer open or closed. You can disengage, or unlock, the drawer by pressing a latch or lever (depends on the model).  Some slides are just lock-out equipped, while other slides have both features.

SPECIAL FEATURES

Additionally, slides can come with features that make opening or closing a drawer more convenient. These include:

EASY-CLOSE VS SELF-CLOSE

An Easy-Close slide includes a closing device, equipped with a damping cylinder, and cooperating springs that engages with the drawer member and assists the final inches of the drawer closing action. Easy-Close (sometimes-called Soft-Close) slides provide assurance that the drawer will close quietly and smoothly every time.

A Self-Close slide, also includes a closing device, with springs, but does not include a damping cylinder.  The engagement of the drawer member is similar, and once engaged with the device, the drawer quickly closes at the last inches of closing distance. Self-close slides are noisier than Easy-Close slides, and sometimes are used as “stay-closed” devices for mobile cart applications.

CHOICE OF FINISH

The majority of slides come in three coated finishes placed over carbon steel slide members: zinc, black electroplate, or white electro-coat. Some slides utilize stainless steel or aluminum material as needed for specific applications.  Zinc is most common plating finish; it features an environmentally friendly base layer of zinc, with either a clear or a black chromate coating over the top.  A clear zinc coating resists moderate levels of corrosion, typically for slides used in non-corrosive environments, like office furniture.  Electro-white (a paint) or black chromate-coated slides offer greater corrosion resistance that is eight-times that of clear zinc. Stainless steel and aluminum material slides offer even greater corrosion-resistant but are available only on select models.

CONCLUSION

The most typical slide used for the laboratory setting has the following features: zinc plated, ball-bearing, side mounted, full extension, and medium duty load capacities. These features are often viewed as the minimum requirement for the laboratory setting. Some instances soft or easy close slides are required which add extra cost but can be an extra value for the client. Always consider what is being put into the drawers before specifying a slide. The specifying of the correct slide application is often the best way of preventing slide issues on your project. Slide specifications are often the most copied and paste portion of the specification from project to project. Please review these specifications with the architect to confirm what slides are required for the project.

Want to learn more? check out this video on drawer slides for 3D examples.

See the rest of the specifying quality wood casework options blog series posts as they become available:

• Plywood Core and Substrate Selection (1)
• Veneer Selection and Criteria (2)
• Lab Grade Finish (3)
• Hardware Selection (4) current