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Nuts · DIN 928 · Application guide

What Are Square Weld Nuts Used For?

Typical applications, the industries that specify square weld nuts, and how to choose the right size, material and finish for the joint.

Square Weld Nuts are used for a square nut with weld projections that is resistance welded to sheet to give a permanent thread. They are manufactured to DIN 928, and the choice of size, property class and finish is driven by the load in the joint and the environment it sits in.

Primary duty
A square nut with weld projections that is resistance welded to sheet to give a permanent thread
Governing standard
DIN 928
Thread size range
M4 to (M16)
Category
Nuts

Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation.

What Are Square Weld Nuts Used For? application image

Square Weld Nuts (DIN 928) are specified where the joint requires a square nut with weld projections that is resistance welded to sheet to give a permanent thread. The sections below cover the typical end-uses by industry, the size and material decisions for each, assembly practice, and the applications this fastener type is not suited to. Stocked across roughly M4 to M16, they cover general to heavy-duty work.

Typical Applications for Square Weld Nuts

The most common settings where these are specified:

  • Automotive bodies: threaded points in panels and brackets.
  • Steel furniture: frames welded before painting.
  • Enclosures: threads in thin sheet with no access behind.
  • Agricultural equipment: welded fixing points.

How to Specify Square Weld Nuts for Your Application

  • Size: Match the nominal size to the mating thread or hole. This product spans M4–M16; check the full table below for the exact dimensions of each size.
  • Locking & grade: Match the strength grade to the bolt, and choose a locking style (nyloc, all-metal, serrated flange) if the joint sees vibration.
  • Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
  • Standard: This product is supplied to DIN 928. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.

Installation & Assembly Practice

  • Run the nut down by hand before applying the wrench to catch cross-threading early.
  • Tighten the nut rather than the bolt head where access allows — the torque-to-preload relation is more consistent.
  • For locking styles, note that nyloc inserts are single-use in critical joints and lose grip above roughly 120 °C.

Common Selection Mistakes with Square Weld Nuts

  • Pairing a high-class bolt with a lower-class nut — the nut strips before the bolt reaches proof load; the nut class must meet or exceed the bolt class.
  • Using a plain nut with a spring washer in severe vibration instead of a prevailing-torque locking nut.
  • Re-using nyloc nuts in critical joints.

Where Square Weld Nuts Are Not the Right Choice

Not on their own — they need a matching bolt or stud — and a plain nut is not a substitute for a locking type under heavy vibration.

Custom manufacturing · Made to drawing

Need a square weld nuts outside the standard range?

Height and across-flats are the two most often changed — a thinner nut for clearance, a larger hex for a tool that is already on the line. Made by cold heading or tapping.

Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

Custom nut manufacturingSend a drawing

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Dimensioned line drawing of M4 Square Weld Nuts to DIN 928. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected.
Pitch P (mm)
0.7
b (mm)
0.8
d2 (mm)
5
d4 (mm)
6.4
h1 (mm)
0.6
h2 (mm)
0.85
Nut height m (mm)
3.5
Width across flats s (mm)
7
Sends the selected values to the quote form below.

Request a Quote

The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (DIN 928)

SizePitch P (mm)b (mm)d2 (mm)d4 (mm)h1 (mm)h2 (mm)Nut height m (mm)Width across flats s (mm)Reference standard
M40.70.856.40.60.853.57DIN 928
M50.8168.20.81.054.29DIN 928
M611.27.59.10.81.25510DIN 928
M81.251.51012.811.556.514DIN 928
M101.51.812.515.61.21.725817DIN 928
M121.75213.517.41.42.3759.519DIN 928
(M14)22.516.820.41.42.47511.422DIN 928
(M16)22.518.822.41.631324DIN 928
Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

How do I choose the right size of Square Weld Nuts?

Match the nominal size to the mating thread or hole. This product is available from M4 to M16; the full dimension table on this page lists each size.

Do Square Weld Nuts need a locking feature?

If the joint sees vibration or cyclic load, use a locking style (nyloc, all-metal lock, or serrated flange) or a thread-locking adhesive. For static joints a standard nut tightened correctly is usually sufficient.

What material should Square Weld Nuts be for outdoor use?

For damp, coastal or chemical environments specify A4 (316) stainless or a suitably coated steel. For indoor or dry use, A2 (304) stainless or zinc-plated steel is normally adequate.

Are Square Weld Nuts made to a recognized standard?

Yes — they are manufactured to DIN 928, so dimensions are interchangeable between suppliers when you quote the standard on your order.

Can I get a quote for Square Weld Nuts in the size and material I need?

Yes. Use the technical drawing and quote form on this page to set the size and options, then send the exact configuration to our team for pricing and lead time.