Whether you’re building a 19″ rack case for touring processors or outfitting a mobile server rack, understanding rack strips is essential. These seemingly simple components—also known as rack rails or rack strip rails—form the backbone of any rack-mounted system, ensuring your equipment stays secure, organized, and compatible with industry standards. In this guide, we’ll explore what rack strips are for, the standards they follow, the differences between single and double angle designs, and why some strips use square holes while others are threaded.
What Are Rack Strips and Why Do They Matter?
Rack strips are metal mounting rails installed vertically inside road cases. Their job is to hold 19-inch rack-mounted equipment such as amplifiers, wireless receivers, processors, and IT gear. By providing a standardized mounting interface, rack strips allow technicians to install and remove gear quickly and safely.
In mobile environments like live events, broadcast trucks, and touring productions, rack rails are critical. They keep equipment stable during transport, reduce the risk of damage from vibration or impact, and make it easier to manage cables and airflow. Without a proper rack rail kit, road cases would be little more than padded boxes.
The Standards Behind Rack Strip Rails
Rack strips are built to conform to the EIA-310 standard, which defines the dimensions and mounting hole patterns for rack-mounted equipment. According to this specification, the width between the mounting rails must be exactly 19 inches (482.6 mm), and the vertical spacing of the holes must follow a precise pattern based on rack units (U).
Each rack unit measures 1.75 inches (44.45 mm) in height. The holes are arranged in repeating three-hole groups per unit, allowing for consistent alignment across devices. This standardization ensures that equipment from different manufacturers can be mounted interchangeably.
Single Angle vs Double Angle Rack Rails
Rack rails come in two main structural profiles: single angle and double angle. The difference lies in their shape, strength, and how they interact with mounted equipment.
Single angle rack strips have an L-shaped cross-section with one mounting face. They’re lightweight, easy to install, and take up minimal space inside the case. This makes them ideal for shallow enclosures or light-duty applications where space efficiency is a priority. Despite their simpler design, single angle rails can still be used in heavy-duty scenarios—especially when the equipment is supported from beneath or when additional bracing is used elsewhere in the case.
Double angle rack strips, by contrast, feature a U-shaped or square profile with two mounting faces. This design offers significantly more rigidity and strength, which is crucial for road cases that carry heavy amplifiers, servers, or rack-mounted power systems. Double angle rails resist flexing under load and provide better support for gear that may be subjected to frequent movement or vibration.
However, there are situations where single angle rails may actually be preferred—even when mounting heavy equipment. One common issue with double angle rack rails is that the inward-facing mounting surface can interfere with the chassis of certain devices. Some server units, for example, have wide flanges, protruding handles, or side-mounted airflow vents that conflict with the inner lip of a double angle rail. In these cases, the extra material of the double angle profile can obstruct proper seating or airflow, making installation difficult or even damaging the equipment.
Single angle rails avoid this problem by presenting a clean, unobstructed mounting face. This can be especially important when mounting gear that requires flush alignment or has tight tolerances around the rack ears. Additionally, single angle rails are often easier to work with when retrofitting older equipment or integrating gear from multiple manufacturers with varying form factors.
Ultimately, the choice between single and double angle rack rails depends on more than just load capacity. Case builders must consider the physical dimensions of the equipment, airflow requirements, mounting depth, and how the rails will interact with other components inside the case. While double angle rails offer superior strength and versatility, single angle rails remain a viable—and sometimes preferable—option for achieving a clean, interference-free installation.
double angle rack strips offers more structural strength and extra mounting options compared to single angle rack strips, but there are situations where single angle rack rails should be used.
Square Holes vs Threaded Holes in Rack Strip Rails
One of the most important design features of rack strips is the hole configuration. These holes are used to mount equipment and come in two main types: square and threaded.
A rack strip with square holes is designed to work with cage nuts—small metal clips that snap into the holes and provide threaded inserts for screws. This system allows users to choose the thread type that matches their equipment, such as M6, 10-32, or 12-24. If a cage nut becomes stripped or damaged, it can be easily replaced without affecting the rack strip rail itself.
This flexibility makes rack strips with square holes especially popular in professional environments. Technicians working with gear from different regions or manufacturers can swap out cage nuts as needed, making square-hole rack rails a future-proof choice for road cases.
Threaded holes, by contrast, are pre-tapped directly into the rack strip. They allow for faster installation since screws can be inserted without additional hardware. Threaded rack rails are often used in fixed installations or cases where the equipment and mounting hardware are standardized.
However, threaded holes come with limitations. If the threads strip, the entire rack strip rail may need to be replaced. They also lock you into a single thread type, which can be inconvenient if your gear changes or if different screws are required. For these reasons, square holes are generally preferred in mobile and professional setups.
A rack strip with square holes allows cage nuts to be used and is easily replicable if the nut strips, while the entire rack rails with threaded holes will need to be replaced if the threads strip.
Choosing the Right Rack Rail Kit for Your Build
Selecting the right rack rail kit depends on several factors: the weight of your equipment, the expected handling conditions, and your need for flexibility.
If you’re building a lightweight or temporary setup, single angle rack strips may be adequate. They’re easy to install and cost-effective. But for touring rigs, broadcast cases, or any application involving heavy gear, double angle rack rails are the better option. Their added strength and mounting versatility make them ideal for demanding environments.
When it comes to hole configuration, rack strips with square holes offer the most adaptability. They allow you to change thread types, replace damaged inserts, and accommodate a wider range of gear. Threaded rack strip rails may be faster to work with, but they’re less forgiving over time.
Ultimately, the goal is to create a mounting system that’s secure, standardized, and easy to maintain. By understanding the differences between rack rail types and hole configurations, you can build road cases that perform reliably and protect your gear wherever you go.