--- title: "What Are All-Metal Lock Nuts Used For?" description: "All-Metal Lock Nuts (ISO 7042 / DIN 980) are used for the clamped counter-face of a bolted joint. Catalogued M5 to M36." url: https://engineeringhardware.com/applications/all-metal-lock-nuts/ source: Engineering Hardware & Fasteners --- # What Are All-Metal Lock Nuts Used For? Nuts · ISO 7042 / DIN 980 · Application guide Typical applications, the industries that specify all-metal lock nuts, and how to choose the right size, material and finish for the joint. All-Metal Lock Nuts are used for the clamped counter-face of a bolted joint. They are manufactured to ISO 7042 / DIN 980, 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:** The clamped counter-face of a bolted joint - **Governing standard:** ISO 7042 / DIN 980 - **Thread size range:** M5 to M36 - **Category:** Nuts Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are All-Metal Lock Nuts Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/All-Metal-Lock-Nuts-—-ISO-7042-／-DIN-980.webp) Application guide for All-Metal Lock Nuts to ISO 7042 / DIN 980. The core duty of the type is the clamped counter-face of a bolted joint. The typical industries, the how-to-specify checklist, assembly practice and the exclusion cases are set out below. Stocked across roughly M5 to M36, they cover general to heavy-duty work. ## Typical Applications for All-Metal Lock Nuts The most common settings where these are specified: - **Maintenance & repair (MRO):** a stocked size for servicing existing plant where the original fastener spec must be matched. - **Fabrication & metalwork:** bench and on-site assembly of steel frames, enclosures and weldments. - **Bolted joints:** the clamping counter-face on studs and bolts across every assembly type. - **Vibration-prone equipment:** where a locking or flanged style resists loosening. - **Frames & weldments:** captive or welded options for repeatable assembly. ## How to Specify All-Metal Lock Nuts for Your Application - **Size:** Match the nominal size to the mating thread or hole. This product spans M5–M36; 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 ISO 7042 / DIN 980. 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 All-Metal Lock 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 All-Metal Lock 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 all-metal lock 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 manufacturing](https://engineeringhardware.com/custom/nuts/)[Send a drawing](https://engineeringhardware.com/custom/nuts/#rfq) ## Technical Drawing Dimensioned line drawing of M5 All-Metal Lock Nuts to ISO 7042 / DIN 980. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Pitch (mm):** 0.8 - **Width across flats s (mm):** 8.0 - **Nut height m (mm):** 6.0 - **Notes:** Deformed-top locking, high-temperature capable ## Dimensions & Specifications (ISO 7042 / DIN 980) | Size | Pitch (mm) | Width across flats s (mm) | Nut height m (mm) | Reference standard | Notes | | --- | --- | --- | --- | --- | --- | | M5 | 0.8 | 8.0 | 6.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M6 | 1.0 | 10.0 | 7.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M8 | 1.25 | 13.0 | 9.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M10 | 1.5 | 16.0 | 11.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M12 | 1.75 | 18.0 | 13.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M14 | 2.0 | 21.0 | 15.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M16 | 2.0 | 24.0 | 17.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M18 | 2.5 | 27.0 | 19.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M20 | 2.5 | 30.0 | 21.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M24 | 3.0 | 36.0 | 24.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M30 | 3.5 | 46.0 | 30.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | | M36 | 4.0 | 55.0 | 36.0 | ISO 7042 / DIN 980 | Deformed-top locking, high-temperature capable | 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](https://engineeringhardware.com/wp-content/uploads/2026/08/09-wire-rod-feed-cold-heading-machine.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/03-thread-rolling-machine-bolt-production.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/05-heat-treatment-baskets-black-bolts.webp) 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](https://engineeringhardware.com/wp-content/uploads/2026/08/23-zinc-plated-bolts-treatment-basket.webp) 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 ### Which industries use All-Metal Lock Nuts? They are commonly specified in maintenance & repair (mro), fabrication & metalwork and bolted joints, among other sectors. ### How do I choose the right size of All-Metal Lock Nuts? Match the nominal size to the mating thread or hole. This product is available from M5 to M36; the full dimension table on this page lists each size. ### Do All-Metal Lock 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 All-Metal Lock 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. ### Can I get a quote for All-Metal Lock 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. ## Related Pages Product page: [All-Metal Lock Nuts — specifications & sizes](https://engineeringhardware.com/fastener/all-metal-lock-nuts/) ### All-Metal Lock Nuts Specification Guides ### Related Fastener Applications