Frequently Asked Questions

A drawer slide, or sometimes called a drawer roller, is a mechanism that allows for telescopic motion in one axis. They 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.

They generally work by allowing one grove component to slide over a rolling component, which allows the entire mechanism to extend or retract. Slides are not motorized but can be coupled with a linear actuator to provide greater stability. Generally, you will use a pair of slides in any application and will most likely encounter two main types: Roller Slides and Ball-Bearing Slides.

Roller Slides

Roller slides consist of two components, the cabinet member and the drawer member, each having its own roller, usually made of plastic. As their names suggest, the cabinet member mounts to a stable or grounded component, i.e. the cabinet, and the drawer member attach to the moving component, i.e. the drawer.

Each roller will fit into the groove found on the other member and will be at opposite ends of the mechanism when fully retracted with the cabinet member’s roller being at the front. As the mechanism is extended, the cabinet member’s roller allows the drawer member to move outwards and the roller of the drawer member follows in the grove of the cabinet member. When fully extended, the two rollers will meet. This two-roller design gives the mechanism horizontal stability and allows for level extension.

 

roller drawer slide

Ball-Bearing

Ball-Bearing Slides make use of ball bearings instead of rollers to allow for telescopic motion. They also make use of a third component, the intermediate member, which interfaces with two sets of ball bearings. The first set interfaces with the groves of the cabinet member and the intermediate member, while the second set interfaces with the groves of the intermediate member and drawer member.

As the mechanism extends, the first component to move is the drawer member, which slides over the ball bearings between itself and the intermediate member. Once the drawer member reaches the end of the ball bearings, the intermediate member will begin to slide along the ball bearings between itself and the cabinet member until fully extended. Like the two-roller design, the ball bearings within each grove of the mechanism give it horizontal stability and allows for a level extension.

 

ball-bearing slide ball-bearing close up

Deciding the mount type is important but more than likely it has already been decided for you by the cabinet design.  There are three mount types for drawer slides: side mount drawer slides, center-mount slides, and undermount slides. When determining the most suitable mount type, you have to consider the space between the cabinet opening and the drawer box.

1. Side-Mount

Side-Mount Drawer slides for side mounting usually come in sets or pairs with slides for each side of the drawer. They come in either roller or ball-bearing mechanisms and require a clearance of at least 1/4″ between the sides of the cabinet opening and the slides.

There are basically two types of drawer slides suitable for side mounting: telescopic extension slides and roller bearing slides.  The simple two-section roller bearing slides are what you will find in the majority of kitchen cabinetry.  They are cheap and widely available but they do not allow for a very long extension and their weight capacity is limited to 50 lbs. 

Telescopic extension slides offer any extension length you require and can hold huge amounts of weight.  Firgelli heavy-duty drawer slides can carry up to 500 lbs of weight with extensions up to a whopping 60 inches.

Installation of both these types of slides is pretty simple and can be done by anyone with a tape measure, screwdriver, and wood screws. 

 

Side mount drawer slides

2. Center Mount

Center Mount Drawer Slides are sold individually as they are under the center and lay flat. the downside of this is that the slide loses its weight capacity when turned however the benefit is that they are hidden even when open, and you only need one per drawer. They are ideal if want to keep a low capacity. required clearance will be determined by thickness style.

 

center mount drawer slides

3. Undermount

Undermount Drawer Slides are the ball-bearing style, and they come in pairs but don't extend the full length that matches the closed length. They are mounted to the cabinet’s sides and are connected to locking devices that go on the underside of the drawer. They require less clearance, usually around 3/16″ to 1/4″ for each side, and maybe a little more work to install. 

If you are looking for quality slides with exceptional weight capacity and extension length, see the links below to Firgelli Automation slides.

10" to 50" Drawer slides with 400-lbs weight capacity

40" to 60" Drawer slides with 500-lbs weight capacity

 

Drawer Slide side under Mount Type

Here are a few considerations and factors that you should consider when selecting or designing around a drawer slide.

Load Rating

Load rating or load capacity is the maximum allowable load or weight the drawer slide can handle before failure. This is usually the main factor in deciding between a regular Drawer Slide or a Heavy-Duty Drawer Slide. This would seem straightforward; just ensure you don’t go over your limit, right? While your drawer slide might be able to hold 300lbs, doesn’t mean your design will.

The load carried by your drawer slides will cause shear stress on the mounting fasteners, for your drawer slides, and cause a corresponding force on your cabinet member. If these components cannot hold 300lbs, your design won’t either. To avoid unexpected failure, you should determine the load capacity for your entire design.

Thickness

The thickness of the slide mechanism is another consideration you will need to factor into your design. The thickness of the mechanism will determine how much clearance you’ll need between your cabinet component and your drawer component. If these factors are constraining your design, then the thickness of your drawer slide will be a very important aspect of selecting the right one. Heavy Duty Slides have a greater thickness compared to normal Drawer Slides.

Mounting

Most commonly, you will mount each drawer slide on opposites sides of each other in a vertical configuration. Although there are some that can be mounted on the bottom side of your drawer component or require only one draw slide, you should always follow what the manufacturer recommends.

If your manufacturer does suggest bottom mount configuration is possible, always check to see if other factors, like load rating, are affected in that configuration. Another aspect to consider, related to mounting, is the hole pattern, which is for your fasteners. If you are getting parts machined for your project, you will ensure you use the right hole pattern for your drawer slide as well as ensuring the holes are level.

Firstly you are going to need a Tape measure. Now that you have a tape measure ready, you are going to remove the drawer from the cabinet. Most drawers require to be fully extended before you can lift them up and it should come right out.

If that doesn’t work, guide the drawer so it is mostly extended, then lift the back of the drawer to pop the wheels out of the guides. If neither of those options works, it may be necessary to use a screwdriver to remove the wheels from the guides.

Since the front face of the drawer works to stop the drawer from entering the cabinet, it should not be measured. Start your measurement at the back of the box and measure to the front of the box and stopping just before the face of the drawer. Round down the number you got for your length, if the drawer is 18 ½ inches long you will need to purchase 18-inch drawer slides.

Note if the sides of the cabinet are not parallel, you will have to use a Linear Bearing Slide Rail