EKINSUN is a custom parts manufacturer that makes cage nuts, captive nuts and rack hardware to drawing when the panel is not the rack standard: an odd square hole, a panel thicker than the cage bands, a stainless nut in a size the series skips, a captive stud instead of a nut. The size ranges are those a distributor stocked in 2026.
A typical request: an enclosure with 8 mm square holes in 3 mm steel, where rack cage nuts fall through the thin band and do not enter the thick one.
Square hole and panel thickness are the two numbers; the thread comes third.
Cage nut types and size ranges
| Type | Standard threads | Square hole | Common materials | Notes |
|---|---|---|---|---|
| Rack cage nut | M4, M5, M6, M8, M10; 10-32 and 12-24 to order | 9.5 mm (3/8 in) rack hole | nickel, yellow-zinc, black steel; 304 stainless M4–M8 | the 19-inch rack standard; snaps in from the rail face |
| Cage nut for enclosure panels | M4–M8 | 8–12 mm holes | zinc steel; 304 | same principle, other hole sizes; made to the hole |
| Captive (clip-on) nut | M6–M30 (clip-on / retaining nut) | panel edge, no hole | spring steel | slides over the panel edge; for hollow sections and edges |
| Sliding block nut for profiles | M3–M8 | profile slot | steel | see T-slot nuts |
| Rack standoff | M3–M6 | — | brass, steel, stainless | see rack-mount enclosure standoffs |
Need cage nuts in a size, thread or material no catalogue lists? EKINSUN is a custom parts manufacturer: we make cage nuts to your drawing, sketch or sample, steel or 304 stainless steel, from 1 piece, quoted in 12 hours and shipped duties paid. Standard sizes can often be supplied from stock; the more pieces, the lower the unit price. All custom fasteners
What the hole, the panel and the rack decide
| Item | Standard value | What happens outside it |
|---|---|---|
| Square hole in a 19-inch rail | 9.5 mm (3/8 in), EIA-310 / DIN 41494 | an 8 or 10.5 mm hole needs a cage bent to that hole |
| Rack unit pitch | 1U = 44.45 mm (1.75 in); holes in a 15.9 / 15.9 / 12.7 mm pattern per U | a chassis drilled to another pitch needs its own rail or bracket |
| Thread, metric racks | M6 (most European and Asian racks), M5 in some | a mixed site keeps both; the cage is the same, the nut differs |
| Thread, US racks | 10-32 (most), 12-24 (older telecom) | made to order in the same cage |
| Panel thickness band | cage nuts are sold in two or three bands for thin and thick rails | a panel outside every band gets a cage with the spring legs formed for it |
| Float | a small amount in each direction | a panel that needs more float uses an oversize cage or a captive plate nut |
What to send for a cage nut that is not standard
- Square hole size, measured across the flats, and whether it is square or rectangular.
- Panel material and thickness, with the finish (a powder-coated rail is thicker than the drawing says).
- Thread: M4–M10, 10-32, 12-24 or another; and whether a nut or a captive stud is wanted.
- Material: nickel or zinc steel for indoor racks, 304 for washdown, 316L for marine.
- Quantity; a prototype enclosure often needs twenty, and twenty is a normal order.
Read the pitch before you order the rack screw. Lay a steel rule along ten thread crests and divide by ten: 10 mm over ten pitches is a 1 mm pitch (M6 coarse), 12.5 mm is M8 coarse, 15 mm is M10 coarse, 17.5 mm is M12 coarse. A reading that is not a round number of millimetres is an inch thread, and a reading that is shorter than the coarse pitch for that diameter is a fine thread. If diameter, pitch and the size range in the table all agree, the part is a standard size: buy it off the shelf, or have it made to order from 1 piece. If any of the three falls outside the table, we make it to your reading. The full measuring routine, including the inch traps
Where the cage nut catalogue stops
| What you need | In the catalogue? | What we make |
|---|---|---|
| M6 or M5 cage nut for a 9.5 mm rack hole, nickel or zinc steel | Yes | Buy it from stock; no one-off competes with a rack cage nut, and every rack distributor has them. Standard parts: ask us too, we may have them in stock. |
| M4–M8 cage nut in 304 stainless | Yes | Standard sizes: buy them off the shelf, or have them made to order from 1 piece. Standard parts: ask us too, we may have them in stock. |
| 10-32 or 12-24 cage nuts in stainless, or M10 in stainless | No | The nut is machined in 304 or 316L and fitted to a standard cage. |
| A cage nut for an 8, 10.5 or 12 mm square hole, or a rectangular hole | No | Cage bent to the hole; nut to your thread; from 1 piece. |
| A panel thicker than every standard band, 3 mm and up | No | Cage legs formed for your panel, or a captive plate nut riveted behind it. |
| A captive stud in place of a nut, or a nut with a sealing washer | No | Machined stud or nut in a cage or plate; sealing washer under the head. |
| A cage nut in aluminium 6061 or 7075 | No | Not a cage nut: the spring cage must be spring steel or stainless. We suggest a clinch nut or a rivet nut in the aluminium panel and say so. |
| A rack standoff of a length the catalogue does not carry | No | Turned to length, see rack-mount enclosure standoffs. |
Materials
| Material | Designation | Where it fits here |
|---|---|---|
| Spring steel cage, zinc or nickel plated | 65Mn / C67S | the standard cage; nut in zinc or nickel steel |
| Stainless 304 cage and nut | 1.4301 / A2 | standard M4–M8; washdown and outdoor cabinets |
| Stainless 316L nut | 1.4404 / A4 | machined to order for marine cabinets, fitted to a 301 / 304 cage |
| Free-machining stainless | 303 / 1.4305 | custom studs and plate nuts |
| Aluminium 6061 | AlMg1SiCu | the panel alloy of many enclosures; takes a rivet nut or clinch nut, not a cage nut |
| Aluminium 7075 | AlZn5.5MgCu | as above; not a cage or nut material here |
Related pages
- every fastener family by standard and size range, all families with standard and size range
- Rack-mount enclosure standoffs, custom-length standoffs for server chassis
- Custom standoffs, hex and round standoffs in any length
- self-clinching nuts, a fixed thread in the panel
- rivet nuts, one-side access
- T-slot nuts, sliding nuts for extrusion frames
Frequently asked questions
The rack hole is 9.5 mm square, so any rack cage nut fits the hole; the thread is what you choose. Most metric racks use M6, some M5; US racks use 10-32, older telecom racks 12-24. Match the thread to the screws already on site.
The spring legs of the cage grip the panel from behind, and a leg formed for 1 mm sheet will not hold on 2.5 mm. Standard cage nuts are sold in two or three bands; a panel outside all of them needs a cage formed for it.
Not a standard one: the cage is sized to the 9.5 mm rack hole. For other holes the cage is bent to the hole and fitted with the nut you need, from 1 piece.
Standard stainless cage nuts are 304 in M4–M8. For 316L, or for 10-32 and 12-24 in stainless, the nut is machined and fitted to a stainless cage.
EKINSUN is a custom parts manufacturer that makes cage nuts, captive nuts, rack studs and rack standoffs to drawing in steel, 304 and 316L stainless, in metric, 10-32 and 12-24 threads, from 1 piece, with a quote within 12 hours.
There is no list price; the drivers are the cage (a bent spring part), the nut material and thread, and quantity. Twenty M6 cages for an odd hole are a small bending job; a stainless 12-24 batch with sealing washers is priced by the parts. The quote separates the two.
Send the square hole and the panel thickness
Hole size across the flats, panel thickness and material, thread, nut or captive stud, quantity. A photo of the rail with a rule across the hole is enough. From 1 piece, quote within 12 hours.