Channel Nut & Spring Nut Guide
The channel nut (or spring nut, strut nut) is the threaded anchor that makes strut work. Picking the right one comes down to one main thing — matching the spring to the depth of your channel — plus thread size and finish. This guide makes that simple, and decodes the part numbers you may have inherited from another brand or an old drawing.
Spring Style by Channel Depth
The spring length matches the nut to the depth of the channel it sits in. This is the most common ordering mistake, so get it right first.
| Spring Style | Fits Channel Depth | Use When |
|---|---|---|
| No Spring | Any depth | You can reach in to hold the nut, or set it at the end. Lowest cost. |
| Short Spring | 13/16" shallow | Shallow / half-height strut |
| Regular Spring | 1-5/8" standard | The everyday choice. Most common. |
| Long Spring | 3-1/4" deep | Deep / double-depth strut |
| Top Spring | All depths | Universal spring across depths |
| EZ / Cone | All depths | Twist-in, one-hand install, no separate spring |
The spring is only a holding aid that keeps the nut at the height you set while you start the bolt. It does not change the nut's thread or strength.
Regular Spring Sizes (1-5/8" Strut)
| Thread | Nut Thickness | EFS SKU |
|---|---|---|
| 1/4-20 | 1/4" | STR4118 |
| 5/16-18 | 3/8" | STR4119 |
| 3/8-16 | 3/8" | STR4121 |
| 1/2-13 | 1/2" | STR4124 |
| 5/8-11 | 7/16" | STR4126 |
| 3/4-10 | 7/16" | STR4127 |
No-spring: STR4165 (1/4-20), STR4168 (3/8-16), STR4171 (1/2-13). Long spring (deep channel): STR4109 (1/2-13). EZ cone: STR4147EZ (3/8-16). Threads run #8-32 through 7/8-9, plus metric M6-M12.
Finishes
- Electro-galvanized zinc — interior and dry, the default.
- 316 stainless — wet, washdown, coastal, chemical. Order the stainless variant of any size (e.g. STR4168S2).
- Hot-dip galvanized — exterior, higher corrosion resistance than zinc.
Decoding Part Numbers (Cross-Reference)
If your drawing or existing run uses another brand's number, match it here:
| EFS SKU | Description | Unistrut | B-Line | PowerStrut |
|---|---|---|---|---|
| STR4118 | 1/4-20 regular spring | P1006-1420 | N224 | PS RS 1/4" |
| STR4124 | 1/2-13 regular spring | P1010 | N225 | PS RS 1/2" |
| STR4109 | 1/2-13 long spring (deep) | P5510 | N725 | PS LS 1/2" |
| STR4168 | 3/8-16 no spring | P3008 | N228WO | PS NS 3/8" |
Full chart: Strut Brand Cross-Reference.
Frequently Asked Questions
What is the difference between a spring nut and a no-spring channel nut?
The spring is a holding aid, not a structural part. A spring nut has a coil spring that pushes the nut against the channel lips so it stays where you set it while you start the bolt, letting you work one-handed and overhead. A no-spring nut is the same threaded nut without the spring; it costs less but you hold it by hand. Both reach the same strength once tightened.
What is a 4109 strut nut?
The 4109 is a 1/2-13 long-spring channel nut, 1/2 inch thick, in zinc. The long spring means it is built for deep 3-1/4 inch channel. It matches Unistrut P5510, B-Line N725, and PowerStrut PS LS 1/2. For standard 1-5/8 inch channel use the regular-spring 1/2-13 (STR4124) instead.
How do I know which spring I need?
Match the spring to the channel depth: regular for standard 1-5/8 inch, long for deep 3-1/4 inch, short for shallow 13/16 inch. If unsure or mixing depths, a no-spring or top-spring nut works across depths.
What is an EZ or cone nut?
An EZ (cone) nut uses a tapered twist-in design instead of a coil spring. Push it in and a quarter turn locks it, giving fast one-hand installation. It works across channel depths and suits high-volume work.
Do these channel nuts fit Unistrut?
Yes. They fit the common 1-5/8 inch strut profile and cross-reference to Unistrut and other brands. For example our 1/2-13 regular spring matches Unistrut P1010.