EKINSUN is a custom parts manufacturer that machines weld nuts to drawing: a non-standard height, a fine or left-hand pitch, a pilot sized to your hole, a 304 or 316L body, or projections placed for your electrode. The size ranges are those a distributor stocked in 2026.
A typical request: a 304 frame that needs a 304 weld nut, M10 fine, with a pilot for the 11 mm hole, where the catalogue has M10 coarse in plain steel and nothing else.
Stainless, fine pitch, pilot: three conditions, each one enough on its own.
Weld nut forms and size ranges
| Form | Standard | Size range | Common materials | Notes |
|---|---|---|---|---|
| Hex weld nut, three projections | DIN 929 | M3–M12 | plain steel; 304 stainless | with or without pilot; the general-purpose nut for brackets and frames |
| Square weld nut, four projections | DIN 928 | M3–M24 | plain steel; 304 stainless | larger weld area; the nut for thicker sheet and higher load |
| Round weld nut with pilot | maker series | M4–M12 | plain steel | the pilot locates the nut in the hole before welding |
| Flanged weld nut | maker series | M6–M12 | plain steel | flange spreads the load and hides a rough hole |
| Hex weld nut without projections (arc weld) | DIN 929 form, plain base | M3–M10 | plain steel | for MIG / TIG fillet welding around the base |
| Weld stud / spot-weld screw | ISO 13918 | M2.5–M10 | copper-plated steel, 304, aluminium | the male counterpart, see weld bolts and studs |
Need weld nuts in a size, thread or material no catalogue lists? EKINSUN is a custom parts manufacturer: we make weld nuts to your drawing, sketch or sample, weldable steel or 304 stainless steel, from 1 piece, quoted in 12 hours and shipped duties paid. Already a catalogue size? Ask us too, we may have it in stock, and larger quantities cost less per piece. All custom fasteners
Which nut for which welding process
| Process | Nut form | Material and finish | Why |
|---|---|---|---|
| Resistance projection welding (press welder) | hex DIN 929 or square DIN 928 with projections | plain, unplated low-carbon steel; 304 for stainless sheet | the projections concentrate the current; plating contaminates the weld and the electrode |
| Spot welding with a hand gun | round or hex with pilot, three projections | plain steel | the pilot keeps the nut on the hole while the gun comes in |
| MIG / TIG arc welding | nut without projections, or a flanged nut | plain steel; 304 / 316L for stainless | a fillet around the base, so projections are not wanted |
| Welding onto a coated or painted frame | — | — | weld before coating, or use a rivet nut or a clinch nut instead |
| Aluminium frame | — | — | steel weld nuts do not weld to aluminium; use a rivet nut, a clinch nut or an aluminium weld stud |
What to send for a weld nut that is not in the table
- Thread and pitch; fine and left-hand pitches are the commonest reason a weld nut is made.
- Height, if the DIN height is too tall for the pocket or too short for the thread engagement you need.
- Pilot diameter and length, matched to the hole in the sheet, and the sheet thickness.
- Projection pattern: three or four, ring or dot, and the electrode you use.
- Sheet material: plain steel, 304, 316L, galvanised (which needs the zinc stripped at the weld).
- Quantity; single pieces are welded onto prototypes every week.
Read the pitch before you order the weld nut. 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 weld nut catalogue stops
| What you need | In the catalogue? | What we make |
|---|---|---|
| Hex DIN 929 M3–M12 or square DIN 928 M3–M24 in plain steel | Yes | Buy it from stock, or have it made to order from 1 piece. No one-off competes with a pressed weld nut. Standard parts: ask us too, we may have them in stock. |
| The same in 304 stainless, M3–M12 hex or M3–M24 square | 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. |
| A weld nut in 316L / 1.4404 | No | Machined from 316L bar with projections milled or formed on the base. |
| A fine-pitch or left-hand weld nut, M10×1.25, M12×1.5, M16 LH | No | Tapped or single-pointed to your reading; the base and projections stay DIN. |
| A pilot sized to an existing hole, or a longer pilot for thick sheet | No | Turned to your hole; pilot length to your sheet. |
| A height above or below DIN, or a reduced across-flats for a tight pocket | No | Machined; the projections are placed for your electrode. |
| A weld nut above M24 | No | Turned from bar; projection or plain base. |
| A weld nut in aluminium 6061 or 7075 for an aluminium frame | No | Not a weld nut: aluminium needs a rivet nut, a clinch nut or an aluminium weld stud, and we say so instead of quoting the wrong part. |
Materials
| Material | Designation | Where it fits here |
|---|---|---|
| Low-carbon steel, plain | S235 / 1010 class | the weld nut: unplated, so the weld is clean |
| Stainless 304 | 1.4301 / A2 | standard hex and square weld nuts for 304 frames |
| Stainless 316L | 1.4404 / A4 | machined to order for marine and chemical frames |
| Free-machining stainless | 303 / 1.4305 | not for welding; listed so it is not specified by mistake |
| Aluminium 6061 | AlMg1SiCu | the frame alloy that needs a rivet nut or clinch nut instead of a weld nut |
| Aluminium 7075 | AlZn5.5MgCu | as above; not weldable with steel nuts |
Related pages
- fastener types chart, all families with standard and size range
- Weld bolts and studs, the male side
- press-in nuts, studs and standoffs, no heat, flush thread
- blind rivet nuts, one-side access, coated sheet
- flange nuts, when a loose nut with a wide base will do
- Large custom nuts, M30 and up, any form
- Schweißmuttern-Tabelle DIN 929 / 928, German: across-flats, hole in the sheet and sheet thickness M3–M16
Frequently asked questions
Zinc on the projections vaporises in the weld, contaminates the joint, pits the electrode and gives an inconsistent weld. Weld nuts are supplied plain and the assembly is plated or painted afterwards.
Hex DIN 929 has three projections and suits general brackets and frames; square DIN 928 has four projections and a larger weld area, so it takes thicker sheet and higher load, and it is standard to M24 where the hex form stops at M12.
Yes, with a 304 weld nut on a 304 frame; the size range covers M3–M12 hex and M3–M24 square. For 316L frames the nut is machined in 316L so the joint stays a single alloy.
The pilot is a short spigot that sits in the sheet hole and locates the nut before the electrode comes down. Its diameter must match the hole, which is why a nut with a pilot for a non-standard hole is made rather than bought.
EKINSUN is a custom parts manufacturer that machines weld nuts in plain steel, 304 and 316L with the pitch, height, pilot and projection pattern the drawing calls for, from 1 piece, with a quote within 12 hours.
No list price. The drivers are material, pitch, whether a pilot or a non-standard height is machined, and quantity. A batch of steel nuts with a special pilot costs little more than the tapping; a single 316L fine-pitch nut is a turned part and priced as one. The quote states the drivers.
Send the thread, the sheet and the hole
Thread and pitch, sheet material and thickness, hole diameter, height or across-flats if they matter, projection pattern, quantity. From 1 piece, quote within 12 hours.