--- title: "What Are Hex Keys (Allen Keys) Used For?" description: "Hex Keys (Allen Keys) (ISO 2936) are used for installing, adjusting or servicing the assembly rather than forming part of it. Catalogued 0.7 mm to 60 mm." url: https://engineeringhardware.com/applications/hex-keys-allen-keys/ source: Engineering Hardware & Fasteners --- # What Are Hex Keys (Allen Keys) Used For? Tools · ISO 2936 · Application guide Typical applications, the industries that specify hex keys (allen keys), and how to choose the right size, material and finish for the joint. Hex Keys (Allen Keys) are used for installing, adjusting or servicing the assembly rather than forming part of it. They are manufactured to ISO 2936, and selection is driven by the nominal size, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Installing, adjusting or servicing the assembly rather than forming part of it - **Governing standard:** ISO 2936 - **Nominal size range:** 0.7 mm to 60 mm - **Category:** Tools Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are Hex Keys (Allen Keys) Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/Hex-Keys-Allen-Keys-—-ISO-2936.webp) The primary duty of Hex Keys (Allen Keys) is installing, adjusting or servicing the assembly rather than forming part of it. Below: the sectors that specify them in volume, the checklist used to select the right size and material for the application, installation notes, and the known limits of the type. Stocked across roughly 0.7 mm to 60 mm, they cover general to heavy-duty work. ## Typical Applications for Hex Keys (Allen Keys) The most common settings where these are specified: - **General machine building:** fastening covers, brackets, motors and sub-assemblies on production equipment. - **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. 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This product spans 0.7 mm–60 mm; check the full table below for the exact dimensions of each size. - **Material:** Choose the material and finish for the service environment — plated steel for general use, stainless for corrosion resistance. - **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 2936. Quoting the standard on your order guarantees interchangeable dimensions between suppliers. ## Where Hex Keys (Allen Keys) Are Not the Right Choice Match the fastener to the load, environment and whether the joint must be reopened; the wrong class or style is the usual cause of joint failure. Custom manufacturing · Made to drawing ## Need a hex keys (allen keys) outside the standard range? A non-standard fastener tool is quoted from the drawing; where one already exists in the catalog, the special is usually a variation on its tooling. Minimum order from 2,000 pieces; samples within 7 days of drawing approval. [Custom fastener tool manufacturing](https://engineeringhardware.com/custom/tools/)[Send a drawing](https://engineeringhardware.com/custom/tools/#rfq) ## Technical Drawing Dimensioned line drawing of 0.7 Hex Keys (Allen Keys) to ISO 2936. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Common bolt sizes:** M1 - **Short leg (mm):** 28 - **Long leg (mm):** 51 ## Dimensions & Specifications (ISO 2936) | Wrench size s (mm) | Common bolt sizes | Short leg (mm) | Long leg (mm) | Reference standard | | --- | --- | --- | --- | --- | | 0.7 | M1 | 28 | 51 | ISO 2936 / DIN 911 | | 0.9 | M1.1 | 28 | 56 | ISO 2936 / DIN 911 | | 1.0 | M1.2 | 32 | 56 | ISO 2936 / DIN 911 | | 1.3 | M1.6 | 36 | 63 | ISO 2936 / DIN 911 | | 1.5 | M2 | 40 | 71 | ISO 2936 / DIN 911 | | 2.0 | M2.5 | 50 | 90 | ISO 2936 / DIN 911 | | 2.5 | M3 | 56 | 100 | ISO 2936 / DIN 911 | | 3.0 | M4 | 63 | 112 | ISO 2936 / DIN 911 | | 4.0 | M5 | 71 | 125 | ISO 2936 / DIN 911 | | 5.0 | M6 | 80 | 140 | ISO 2936 / DIN 911 | | 6.0 | M8 | 90 | 160 | ISO 2936 / DIN 911 | | 7.0 | --- | 100 | 180 | ISO 2936 / DIN 911 | | 8.0 | M10 | 112 | 200 | ISO 2936 / DIN 911 | | 9.0 | --- | 112 | 200 | ISO 2936 / DIN 911 | | 10.0 | M12 | 125 | 224 | ISO 2936 / DIN 911 | | 12.0 | M14 | 140 | 250 | ISO 2936 / DIN 911 | | 14.0 | M16 | 160 | 280 | ISO 2936 / DIN 911 | | 17.0 | M20 | 180 | 315 | ISO 2936 / DIN 911 | | 19.0 | M22 | 200 | 355 | ISO 2936 / DIN 911 | | 22.0 | M24 | 224 | 400 | ISO 2936 / DIN 911 | | 24.0 | M27 | 250 | 450 | ISO 2936 / DIN 911 | | 27.0 | M30 | 280 | 500 | ISO 2936 / DIN 911 | | 32.0 | M36 | 315 | 560 | ISO 2936 / DIN 911 | | 36.0 | M42 | 355 | 630 | ISO 2936 / DIN 911 | | 41.0 | M48 | 400 | 710 | ISO 2936 / DIN 911 | | 46.0 | --- | 450 | 800 | ISO 2936 / DIN 911 | | 50.0 | --- | 500 | 900 | ISO 2936 / DIN 911 | | 55.0 | --- | 500 | 900 | ISO 2936 / DIN 911 | | 60.0 | --- | 560 | 1000 | ISO 2936 / DIN 911 | 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 ### What are Hex Keys (Allen Keys) used for? Installing, adjusting or servicing the assembly rather than forming part of it. They are supplied to ISO 2936. ### Which industries use Hex Keys (Allen Keys)? They are commonly specified in general machine building, maintenance & repair (mro) and fabrication & metalwork, among other sectors. ### How do I choose the right size of Hex Keys (Allen Keys)? Select on nominal size and on the fit the assembly requires. This product is available from 0.7 mm to 60 mm; the full dimension table on this page lists each size. ### Are Hex Keys (Allen Keys) made to a recognized standard? Yes — they are manufactured to ISO 2936, so dimensions are interchangeable between suppliers when you quote the standard on your order. ### Can I get a quote for Hex Keys (Allen Keys) 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: [Hex Keys (Allen Keys) — specifications & sizes](https://engineeringhardware.com/fastener/hex-keys-allen-keys/) ### Hex Keys (Allen Keys) Specification Guides ### Related Fastener Applications