--- title: "What Are T-Slot Nuts Used For?" description: "T-Slot Nuts (DIN 508) are used for clamping fixtures, vises and workpieces to a machine table through its T-slots. Catalogued M5 to M24." url: https://engineeringhardware.com/applications/t-slot-nuts/ source: Engineering Hardware & Fasteners --- # What Are T-Slot Nuts Used For? Nuts · DIN 508 · Application guide Typical applications, the industries that specify t-slot nuts, and how to choose the right size, material and finish for the joint. T-Slot Nuts are used for clamping fixtures, vises and workpieces to a machine table through its T-slots. They are manufactured to DIN 508, 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:** Clamping fixtures, vises and workpieces to a machine table through its T-slots - **Governing standard:** DIN 508 - **Thread size range:** M5 to M24 - **Category:** Nuts Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are T-Slot Nuts Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/T-Slot-Nuts-—-DIN-508.webp) T-Slot Nuts are used primarily for clamping fixtures, vises and workpieces to a machine table through its T-slots. This page lists the industries and assemblies where they are specified, the selection criteria that matter for each application, installation practice, and the cases where a different fastener type is the correct choice. Parts are supplied to DIN 508. Stocked across roughly M5 to M24, they cover general to heavy-duty work. ## Typical Applications for T-Slot Nuts The most common settings where these are specified: - **Vibration-prone equipment:** where a locking or flanged style resists loosening. - **Frames & weldments:** captive or welded options for repeatable assembly. - **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. ## How to Specify T-Slot Nuts for Your Application - **Size:** Match the nominal size to the mating thread or hole. This product spans M5–M24; 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 508. 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 T-Slot 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 T-Slot 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 t-slot 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 T-Slot Nuts to DIN 508. Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **T-slot width (mm):** 6 - **Nut width b (mm):** 8.0 - **Total height h (mm):** 8.0 - **Key height h1 (mm):** 4.5 - **Hook width e (mm):** 6.4 ## Dimensions & Specifications (DIN 508) | Thread size | T-slot width (mm) | Nut width b (mm) | Total height h (mm) | Key height h1 (mm) | Hook width e (mm) | Reference standard | | --- | --- | --- | --- | --- | --- | --- | | M5 | 6 | 8.0 | 8.0 | 4.5 | 6.4 | DIN 508 / GN505 | | M6 | 8 | 10.0 | 10.0 | 5.5 | 8.4 | DIN 508 / GN505 | | M8 | 10 | 12.0 | 12.0 | 7.0 | 10.4 | DIN 508 / GN505 | | M8 | 12 | 14.0 | 12.0 | 7.0 | 12.4 | DIN 508 / GN505 | | M10 | 12 | 14.0 | 14.0 | 8.0 | 12.4 | DIN 508 / GN505 | | M10 | 14 | 16.0 | 14.0 | 8.0 | 14.4 | DIN 508 / GN505 | | M12 | 14 | 16.0 | 17.0 | 10.0 | 14.4 | DIN 508 / GN505 | | M12 | 18 | 20.0 | 17.0 | 10.0 | 18.4 | DIN 508 / GN505 | | M16 | 18 | 20.0 | 20.0 | 12.0 | 18.4 | DIN 508 / GN505 | | M16 | 22 | 25.0 | 20.0 | 12.0 | 22.4 | DIN 508 / GN505 | | M20 | 22 | 25.0 | 25.0 | 15.0 | 22.4 | DIN 508 / GN505 | | M20 | 28 | 32.0 | 25.0 | 15.0 | 28.4 | DIN 508 / GN505 | | M24 | 28 | 32.0 | 30.0 | 18.0 | 28.4 | DIN 508 / GN505 | 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 material should T-Slot 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 T-Slot Nuts made to a recognized standard? Yes — they are manufactured to DIN 508, so dimensions are interchangeable between suppliers when you quote the standard on your order. ### What are T-Slot Nuts used for? Clamping fixtures, vises and workpieces to a machine table through its T-slots. They are supplied to DIN 508. ### Which industries use T-Slot Nuts? They are commonly specified in vibration-prone equipment, frames & weldments and general machine building, among other sectors. ### Can I get a quote for T-Slot 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: [T-Slot Nuts — specifications & sizes](https://engineeringhardware.com/fastener/t-slot-nuts/) ### T-Slot Nuts Specification Guides ### Related Fastener Applications