--- title: "What Are Self-Undercutting Mechanical Anchors Used For?" description: "Self-Undercutting Mechanical Anchors (Trade series (HDA-T)) are used for self-undercutting threaded anchorage in existing concrete. Catalogued M10 to M20." url: https://engineeringhardware.com/applications/self-undercutting-mechanical-anchors/ source: Engineering Hardware & Fasteners --- # What Are Self-Undercutting Mechanical Anchors Used For? Anchors & Concrete Fixings · Trade series (HDA-T) · Application guide Typical applications, the industries that specify self-undercutting mechanical anchors, and how to choose the right size, material and finish for the joint. Self-Undercutting Mechanical Anchors are used for self-undercutting threaded anchorage in existing concrete. They are manufactured to Trade series (HDA-T), and selection is driven by the thread size, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Self-undercutting threaded anchorage in existing concrete - **Governing standard:** Trade series (HDA-T) - **Thread size range:** M10 to M20 - **Category:** Anchors & Concrete Fixings Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are Self-Undercutting Mechanical Anchors Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/09/Hilti-HDA-T-Self-Undercutting-Mechanical-Anchors.webp) The primary duty of Self-Undercutting Mechanical Anchors is self-undercutting threaded anchorage in existing concrete. 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 M10 to M20, they cover general to heavy-duty work. ## Typical Applications for Self-Undercutting Mechanical Anchors The most common settings where these are specified: - **Concrete base plates:** post-installed threaded anchors for steel columns and equipment frames. - **Bridge retrofit:** removable structural attachments in existing cracked concrete. - **Plant installation:** machine hold-downs where edge distance needs design control. - **Infrastructure maintenance:** anchored rails, barriers and brackets in existing concrete. 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This product spans M10–M20; 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 Trade series (HDA-T). Quoting the standard on your order guarantees interchangeable dimensions between suppliers. ## Where Self-Undercutting Mechanical Anchors 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 self-undercutting mechanical anchors outside the standard range? Embedment depth, thread size, body length and corrosion protection are the variables; capacity remains a concrete design value, not a property of the anchor alone. Made by hot forging or thread rolling. Minimum order from 2,000 pieces; samples within 7 days of drawing approval. [Custom anchor & concrete fixing manufacturing](https://engineeringhardware.com/custom/anchors/)[Send a drawing](https://engineeringhardware.com/custom/anchors/#rfq) ## Technical Drawing Dimensioned line drawing of M10 Self-Undercutting Mechanical Anchors to Trade series (HDA-T). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Available embedment options (mm):** 100 / 125 / 190 / 250 - **Maximum fixture thickness options (mm):** 20 / 30 / 40 / 50 / 60 / 100 - **Finish:** electro-zinc plated, minimum 5 µm - **Base material:** cracked and non-cracked concrete - **Load cases:** static / dynamic / seismic ## Dimensions & Specifications (Trade series (HDA-T)) | Anchor size | Available embedment options (mm) | Maximum fixture thickness options (mm) | Finish | Base material | Load cases | | --- | --- | --- | --- | --- | --- | | M10 | 100 / 125 / 190 / 250 | 20 / 30 / 40 / 50 / 60 / 100 | electro-zinc plated, minimum 5 µm | cracked and non-cracked concrete | static / dynamic / seismic | | M12 | 100 / 125 / 190 / 250 | 20 / 30 / 40 / 50 / 60 / 100 | electro-zinc plated, minimum 5 µm | cracked and non-cracked concrete | static / dynamic / seismic | | M16 | 100 / 125 / 190 / 250 | 20 / 30 / 40 / 50 / 60 / 100 | electro-zinc plated, minimum 5 µm | cracked and non-cracked concrete | static / dynamic / seismic | | M20 | 100 / 125 / 190 / 250 | 20 / 30 / 40 / 50 / 60 / 100 | electro-zinc plated, minimum 5 µm | cracked and non-cracked concrete | static / dynamic / seismic | 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 ### How do I choose the right size of Self-Undercutting Mechanical Anchors? Match the nominal size to the mating thread or hole. This product is available from M10 to M20; the full dimension table on this page lists each size. ### What material should Self-Undercutting Mechanical Anchors 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 Self-Undercutting Mechanical Anchors made to a recognized standard? Yes — they are manufactured to Trade series (HDA-T), so dimensions are interchangeable between suppliers when you quote the standard on your order. ### What are Self-Undercutting Mechanical Anchors used for? Self-undercutting threaded anchorage in existing concrete. They are supplied to Trade series (HDA-T). ### Can I get a quote for Self-Undercutting Mechanical Anchors 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: [Self-Undercutting Mechanical Anchors — specifications & sizes](https://engineeringhardware.com/fastener/self-undercutting-mechanical-anchors/) ### Self-Undercutting Mechanical Anchors Specification Guides ### Related Fastener Applications