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Four Things to Know About Cantilever (Aka 2-Post) Shelves

Four Things to Know About Cantilever (Aka 2-Post) Shelves

Posted by NavePoint on May 18th 2021

Welcome back to our blog series to learn about the types of rack mount shelves. If you have a 4-Post rack or cabinet, make sure you first check out the Types of shelves for Equipment Racks and Cabinets to consider your options. If you have a 2-Post rack or cabinet, cantilever (aka 2-Post) shelves are your only option. In this blog, we will discuss the four things you need to know about the cantilever shelves.

Depth and Weight Capacity

At NavePoint, we currently offer cantilever shelves with depths ranging from 6” to 22” which should fit most application’s needs.

Just like our previous blog about Things to consider when deciding between a 2-Post or 4-Post Rack, 2-Post structures have a physical disadvantage in terms of weight capacity compared to their 4-Post counterpart. At NavePoint, our cantilever shelves have an industry matching weight capacity range from 22 lbs. to 110 lbs. In our previous blog, Top Three Things to Know About Fixed 4-Post Shelves, we discussed the reasons that shelf lips matter. Although it does not matter whether the shelf lip is bent upward or downward, having a shelf lip or two (one in both front and back) can increase the shelf's ability to handle the concentrated load.

Rack Units Matter

Our NavePoint 1U Vented Cantilever Shelf 14" (350mm) Deep with Lip have a depth of 14” and can handle 44 lbs. or load in a 1U package. Sometimes, customers are confused on why their shelf is sagging with only 30 lbs. of load when the shelf is rated for 44 lbs. The rack’s cabinet's mounting rails are almost always to blame. We will discuss the importance of good mounting rail designs and why thicker mounting rails are often better in a future blog, so make sure to subscribe so you won’t miss out.

Currently, NavePoint offers 1U and 2U cantilever shelves and we are always looking to add more options to our collection. Without going into the engineering details regarding the free body diagram of a cantilever system and the movements being applied to the vertical mounting rails, the key takeaway is that the larger the rack units of a cantilever shelf, less bending on the vertical mounting rails and less sag.

Mounted Toward the Front or Back

All of NavePoint’s 2-Post racks and most of the 2-Post racks (known brands) in the market will support a cantilever shelf that is mounted toward the front instead of the typical orientation toward the back. Many of NavePoint's 2-Post racks like NavePoint 22U 2-Post Open Frame Rack with Casters have duel mounting rails which means you can mount a cantilever toward the front and another one toward the back to achieve a center mount configuration.

A “center mount” shelf is a pair of two cantilever shelves with lips facing down and an extension beyond the mounting lips to minimize the gap between the shelves when assembled.

Vents Can Be Functional

Trying to not sound like an answering machine, our previous blog, Top Three Things to Know About Fixed 4-Post Shelves, explained how shelf vents started from a method to improve the airflow inside a cabinet and evolved into an equipment security and cable management feature. They are used in conjunction with plastic clips to keep NAS systems in place, or cable ties are looped through for cable management. Too many vents can negatively affect part quality issues.


Overall, if you have a 2-Post rack, a cantilever (aka 2-post) shelf is the only choice. Four things to consider are the mounting depths and the weight capacity, why rack units matter, the difference between a regular cantilever shelf and a center mount shelf, and how shelf vents can be functional. People are always finding new ways to utilize cantilever shelves in their cabinet structure and NavePoint has worked with server solution developers to find creative ways to mount equipment on 2-Post shelves in a 4-Post cabinet that maximizes the overall server performance density of the system.

Contact NavePoint’s sales or customer service team at 888-505-1363 to learn more about how we may be able to help with your specific needs!

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