A spring nut is one of the smallest parts on an MEP job and one of the most ordered. Every pipe hanger, cable tray bracket and duct support built on strut channel depends on it, which is why contractors in Dubai, Sharjah and Abu Dhabi buy spring nuts by the thousand. Choosing the wrong size, spring length or finish is easy to avoid at the ordering stage and expensive to fix once the ceiling is closed.
This guide explains how spring nuts work, which size and type suit each channel, which finish to use in UAE conditions, and how to install them so they hold.
What is a spring nut?
A spring nut — also called a channel nut or strut nut — is a rectangular threaded nut that fits inside slotted strut channel. Two grooves across its top face lock onto the inturned lips of the channel when the bolt is tightened, so the joint grips the channel mechanically instead of relying on friction alone.
A coil spring underneath presses the nut up against the lips while you position it. That keeps the nut where you put it, even when you are working overhead, until the bolt or threaded rod goes in. The result is a fixing point you can place anywhere along the channel — the reason spring nuts are the standard way to attach pipe clamps, threaded rod drops, cantilever arms and cable tray supports to strut.
Types of spring nut
| Type | Use with | Choose it when |
| Long-spring nut | Deep channel, typically 41 × 41 mm | You are using standard-depth strut — the usual choice for most supports |
| Short-spring nut | Shallow channel, typically 41 × 21 mm | The support is low-profile: wall-mounted runs, tight ceiling voids, lighter loads |
| Channel nut without spring | Compatible channel of any depth | The nut is fitted from above or held by gravity, so it doesn’t need a spring to stay in place |
Spring nuts are normally used with a square channel washer on the outside of the channel. The washer spreads the load across the slot and keeps fixtures square — on slotted channel it is essential.
Spring nut sizes: which thread do you need?
Spring nuts are sized by their metric thread, which must match the bolt or threaded rod you are connecting. When people search for a “spring nut 10mm”, “8mm” or “6mm”, they mean the thread — M10, M8 or M6 — not the size of the nut body.
| Thread | Typical uses |
| M6 | Light electrical work, small cable tray brackets, instrument and sign fixings |
| M8 | Cable tray brackets, light pipe clamps, small duct supports |
| M10 | Threaded rod drops for pipe hangers and cable tray trapezes — one of the most widely used sizes |
| M12 | Heavier pipework, ductwork and equipment supports; trapezes carrying larger loads |
| M16 | Heavy-duty supports — check the nut and channel ratings carefully |
Safe loads depend on the nut, the channel profile and the channel’s steel thickness, so use the channel manufacturer’s published load data rather than a generic figure. As a rule, heavier-gauge channel gives a stronger, more slip-resistant connection.
Match the spring nut to the channel
- 41 × 41 mm (deep) channel: use a long-spring nut so the spring reaches the channel base.
- 41 × 21 mm (shallow) channel: use a short-spring nut; a long spring will not fit.
- Lip profile: nuts and channel from different makers do not always engage fully. Buy them as a system, or test a sample before ordering in bulk.
- Thread: match the nut to the threaded rod or bolt, and keep one thread size per support to avoid mix-ups on site.
Which finish for UAE conditions?
| Finish | Best for | Notes |
| Electro-galvanised (zinc-plated) | Indoor: ceiling voids, plant rooms, service shafts | Thin zinc layer; economical; not intended for outdoor exposure |
| Hot-dip galvanised (HDG) | Outdoor work, car parks, roofs, humid areas | Much thicker zinc coating; pair with HDG channel and fixings |
| Stainless steel 304 (A2) | Clean indoor or sheltered areas, food and pharma facilities | No coating to damage when cutting or adjusting |
| Stainless steel 316 (A4) | Coastal sites, marine work, chemical and wash-down areas | Best corrosion resistance for salt exposure |
Keep finishes consistent across a support. In wet or outdoor conditions, mixing stainless nuts with galvanised channel can speed up corrosion of the zinc around the joint. For coastal projects, our guide to SS304 vs SS316 fasteners explains when 316 is worth the extra cost.
Spring nuts in cable tray installations
Cable tray is usually carried on strut: a trapeze hung from two threaded rod drops, a cantilever arm on a wall or column, or a floor-mounted post. Spring nuts provide the fixing points throughout the support:
- fixing the channel to threaded rod drops, beam clamps and walls;
- attaching cantilever arms and brackets;
- securing the cable tray to its supports with hold-down clamps.
Because cable tray runs are long and repetitive, nuts that stay exactly where you place them save real time on every support.
How to install a spring nut
- Hold the nut grooves-up and push it into the channel slot, compressing the spring.
- Turn it 90° clockwise so the grooves sit square under the channel lips.
- Slide it to the fixing position — the spring holds it there.
- Place the fixture and a square channel washer where required, then insert the bolt or threaded rod.
- Tighten to the torque recommended by the channel manufacturer, checking that both grooves have seated on the lips.
- Give the fixing a firm pull before it takes load. A nut that has twisted in the channel will move.
Common spring nut mistakes on site
- A long-spring nut in shallow channel (it won’t seat) or a short spring in deep channel (it won’t stay in position).
- An ordinary hex nut used inside the channel — it cannot grip the lips and will slip under load.
- Under-tightening, so the grooves never bite into the lips; or over-tightening, which can distort the channel.
- Indoor zinc-plated nuts used on roofs, in car parks or near the coast, where they rust quickly.
- Nuts and channel from different suppliers combined without checking the fit.
- Re-using nuts with damaged threads or flattened springs.
Build the complete support
A spring nut is one part of a support kit. Order the matching parts together so sizes and finishes line up: spring nuts and GI/MS spring nuts, threaded rod from our stud and threaded rod range, beam clamps for fixing to steelwork, and washers.
Ordering spring nuts for a project? Send us the thread size, spring type (long, short or none), finish, quantity and the channel you’re using. Al Hafoof has supplied fasteners to UAE contractors since 1997 and supplies spring nuts in bulk — we’ll quote the matching washers, threaded rod and beam clamps in the same reply. Request a quote or message us on WhatsApp.
Frequently asked questions
What size spring nut do I need for 41 × 41 channel?
Use a long-spring nut with a thread that matches your bolt or threaded rod. The 41 × 41 dimension decides the spring length, not the thread size — M10 and M12 are the most common threads for hangers and supports.
What is the difference between a spring nut and a channel nut?
A spring nut is a channel nut with a spring fitted underneath. Both lock onto the channel lips in the same way; the spring simply holds the nut in position while you install the fixture, which makes overhead work faster.
Can spring nuts be used outdoors in the UAE?
Yes, if the finish suits the exposure. Use hot-dip galvanised nuts with HDG channel for general outdoor work, and stainless steel 316 near the coast or in chemical areas. Electro-galvanised (zinc-plated) nuts are meant for indoor use.
What does “spring nut 10mm” mean?
It means a spring nut with an M10 thread, to suit 10 mm bolts or M10 threaded rod. Spring nuts are described by their thread, not the size of the nut body.
Are spring nuts used for cable tray?
Yes. Cable tray is normally supported on strut channel, and spring nuts provide the fixing points for the channel, the brackets and the hold-down clamps that secure the tray.
Do you supply spring nuts in bulk?
Yes. Al Hafoof supplies spring nuts in bulk to contractors across the UAE. Send us your sizes and quantities for a quote.
