--- title: "What Are Woodruff Keys Used For?" description: "Woodruff Keys (DIN 6888) are used for transmitting torque between a shaft and a hub. Catalogued 1 mm to 10 mm." url: https://engineeringhardware.com/applications/woodruff-keys/ source: Engineering Hardware & Fasteners --- # What Are Woodruff Keys Used For? Keys · DIN 6888 · Application guide Typical applications, the industries that specify woodruff keys, and how to choose the right size, material and finish for the joint. Woodruff Keys are used for transmitting torque between a shaft and a hub. They are manufactured to DIN 6888, and selection is driven by the key section, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Transmitting torque between a shaft and a hub - **Governing standard:** DIN 6888 - **Key section range:** 1 mm to 10 mm - **Category:** Keys Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are Woodruff Keys Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/Woodruff-Keys-—-DIN-6888.webp) Application guide for Woodruff Keys to DIN 6888. The core duty of the type is transmitting torque between a shaft and a hub. The typical industries, the how-to-specify checklist, assembly practice and the exclusion cases are set out below. Stocked across roughly 1 mm to 10 mm, they cover general to heavy-duty work. ## Typical Applications for Woodruff Keys The most common settings where these are specified: - **Pumps & fans:** driving rotating components without slip. - **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. - **Power transmission:** locking pulleys, sprockets and couplings to a shaft. ## How to Specify Woodruff Keys for Your Application - **Size:** Select on key section, and confirm it against the mating feature in the assembly. This product spans 1 mm–10 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 DIN 6888. Quoting the standard on your order guarantees interchangeable dimensions between suppliers. ## Where Woodruff Keys Are Not the Right Choice Not for very high reversing torque without an interference fit, and not as an axial retainer. Custom manufacturing · Made to drawing ## Need a woodruff keys outside the standard range? Width, height, length, taper and material are specifiable, and the keyway drawing matters as much as the key itself. Made by milling or broaching & serration. Minimum order from 2,000 pieces; samples within 7 days of drawing approval. [Custom machine key manufacturing](https://engineeringhardware.com/custom/keys/)[Send a drawing](https://engineeringhardware.com/custom/keys/#rfq) ## Technical Drawing Dimensioned line drawing of 1.0 Woodruff Keys to DIN 6888. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Disc diameter d (mm):** 4 - **Key height h (mm):** 1.4 - **Chord length l (mm):** 3.7 - **Shaft groove depth t1 (mm):** 1.0 - **Hub groove depth t2 (mm):** 0.6 ## Dimensions & Specifications (DIN 6888) | Key width b (mm) | Disc diameter d (mm) | Key height h (mm) | Chord length l (mm) | Shaft groove depth t1 (mm) | Hub groove depth t2 (mm) | Reference standard | | --- | --- | --- | --- | --- | --- | --- | | 1.0 | 4 | 1.4 | 3.7 | 1.0 | 0.6 | DIN 6888 / ISO 3912 | | 1.5 | 4 | 1.4 | 3.7 | 1.0 | 0.6 | DIN 6888 / ISO 3912 | | 2.0 | 5 | 1.8 | 4.7 | 1.4 | 0.6 | DIN 6888 / ISO 3912 | | 2.0 | 6 | 2.6 | 5.7 | 2.0 | 0.8 | DIN 6888 / ISO 3912 | | 2.5 | 7 | 3.0 | 6.8 | 2.3 | 1.0 | DIN 6888 / ISO 3912 | | 3.0 | 7 | 3.0 | 6.8 | 2.3 | 1.0 | DIN 6888 / ISO 3912 | | 3.0 | 9 | 4.0 | 8.8 | 3.2 | 1.0 | DIN 6888 / ISO 3912 | | 3.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 | | 4.0 | 9 | 4.0 | 8.8 | 3.2 | 1.0 | DIN 6888 / ISO 3912 | | 4.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 | | 4.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 | | 5.0 | 10 | 4.5 | 9.8 | 3.5 | 1.2 | DIN 6888 / ISO 3912 | | 5.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 | | 5.0 | 16 | 7.5 | 15.7 | 6.3 | 1.4 | DIN 6888 / ISO 3912 | | 6.0 | 13 | 6.0 | 12.7 | 5.0 | 1.4 | DIN 6888 / ISO 3912 | | 6.0 | 16 | 7.5 | 15.7 | 6.3 | 1.4 | DIN 6888 / ISO 3912 | | 6.0 | 19 | 9.0 | 18.6 | 7.5 | 1.8 | DIN 6888 / ISO 3912 | | 8.0 | 19 | 9.0 | 18.6 | 7.5 | 1.8 | DIN 6888 / ISO 3912 | | 8.0 | 22 | 11.0 | 21.6 | 9.3 | 1.8 | DIN 6888 / ISO 3912 | | 10.0 | 22 | 11.0 | 21.6 | 9.3 | 1.8 | DIN 6888 / ISO 3912 | | 10.0 | 25 | 13.0 | 24.5 | 11.0 | 2.3 | DIN 6888 / ISO 3912 | 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 ### Are Woodruff Keys made to a recognized standard? Yes — they are manufactured to DIN 6888, so dimensions are interchangeable between suppliers when you quote the standard on your order. ### What are Woodruff Keys used for? Transmitting torque between a shaft and a hub. They are supplied to DIN 6888. ### Which industries use Woodruff Keys? They are commonly specified in power transmission, gearboxes & motors and pumps & fans, among other sectors. ### How do I choose the right size of Woodruff Keys? Select on key section and on the fit the assembly requires. This product is available from 1 mm to 10 mm; the full dimension table on this page lists each size. ### Can I get a quote for Woodruff 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: [Woodruff Keys — specifications & sizes](https://engineeringhardware.com/fastener/woodruff-keys/) ### Woodruff Keys Specification Guides ### Related Fastener Applications