Rack Screw Holes: Understanding the Differences
Importance of Rack Screw Holes
When working with server racks or other types of racks, you must be able to secure your devices in place. To do this, you will have to find the screws or fasteners that fit within the holes in your rack. There is no single set standard when it comes to rack screw holes, so it is important to understand the various options, when they should be used, and other relevant information about this topic.
Threaded Holes
Threaded holes are very popular and come in a variety of different sizes. A threaded hole allows a screw to fit in naturally and securely since they guide the screw in more easily. Most people work with threaded holes in other projects as well, which makes this an option that is quite familiar. 
While not as popular as other options, you can still find great hardware that uses threaded holes, including the following:
- Telco Relay 2 Post Racks – Telco relay racks are essential in most data centers and other facilities to allow for wires to come in and stay organized. Mount all DEMARK equipment securely using threaded holes.
- Secure Vertical 5U Wall Mount Rack – This wall mount uses threaded holes for both M6 and 12-24 screws, so it is convenient and will keep your hardware safe.
Round Unthreaded Holes
Round unthreaded holes
were first brought to market for server racks by IBM, but they have gained some popularity since. You can find many different OEM rails and other equipment from Dell, HP, and IBM that fit round unthreaded holes. This type of rack hole, however, has fallen out of favor in recent years because of the universal square rack holes. While primarily found in older racks now, hardware for this type of hole is still available in some places.
Universal Square Rack Holes
Square rack holes are the most popular on new server racks today. They have square holes that are 3/8’’ by 3/8’’ and are typically on steel uprights that can be anywhere from .085’’ to .11’’ thick, which makes them strong enough to support virtually any equipment.
This type of hole has made it much easier for manufacturers to develop ‘quick rails’. These rails cut down on the installation time, and also help to avoid errors when installing new devices. Another nice thing about square rack holes is that they can be converted to a threaded hole quickly and inexpensively by using a cage nut, which will simply snap into the square hole.
Some examples of hardware that uses universal square rack holes include:
- TechEdge 2 Post Racks – This 2-post rack has a capacity for up to 1000lbs, and makes installation quick and easy without requiring any tools.
- Rail Kits – These rails are made to fit a variety of server devices, and will fit on many other types of hardware as well. Works with universal square rack holes.
- Server Cabinet Enclosures – Most new server cabinet enclosures work well with universal square rack holes.
- Open Frame Server Racks – These types of racks use universal square rack holes, but have an open design without the complete enclosure of rack cabinets.
When buying a server rack, it is important to know what types of rack screw holes it comes with. In the bigger picture of data center planning and management, it is easy to overlook this detail. By getting this information early, however, it ensures you are prepared for the future.
What are different types of server rack holes?
Server racks can have either square, threaded or circle holes. Square holes require cagenuts, threaded holes can accept screws directly, circle holes need an adapter.
