--- title: "What Are Drop-In Anchors (Internally Threaded) Used For?" description: "Drop-In Anchors (Internally Threaded) (Trade series (displacement-controlled anchor)) are used for providing a flush, internally threaded fixing point in con…" url: https://engineeringhardware.com/applications/drop-in-anchors/ source: Engineering Hardware & Fasteners --- # What Are Drop-In Anchors (Internally Threaded) Used For? Anchors & Concrete Fixings · Trade series (displacement-controlled anchor) · Application guide Typical applications, the industries that specify drop-in anchors (internally threaded), and how to choose the right size, material and finish for the joint. Drop-In Anchors (Internally Threaded) are used for providing a flush, internally threaded fixing point in concrete so the bolt — and the fixture with it — can be removed and replaced without disturbing the anchor. They are manufactured to Trade series (displacement-controlled anchor), and selection is driven by the thread size, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Providing a flush, internally threaded fixing point in concrete so the bolt — and the fixture with it — can be removed and replaced without disturbing the anchor - **Governing standard:** Trade series (displacement-controlled anchor) - **Thread size range:** M6 to M16 - **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 Drop-In Anchors (Internally Threaded) Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/08/Female-Threaded-Anchors.webp) Drop-In Anchors (Internally Threaded) are used primarily for providing a flush, internally threaded fixing point in concrete so the bolt — and the fixture with it — can be removed and replaced without disturbing the anchor. 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 Trade series (displacement-controlled anchor). Stocked across roughly M6 to M16, they cover general to heavy-duty work. ## Typical Applications for Drop-In Anchors (Internally Threaded) The most common settings where these are specified: - **Fit-out & drylining:** fixing to plasterboard, block and hollow wall where there is no solid backing. - **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. - **Structural fixing to concrete:** base plates, brackets, rails and steelwork bolted to a concrete slab or wall. Product catalog ## Related Drop-In Anchors products [![Anchors Hot Sale Inserts Drop in Expansion Anchor Copper 304 Stainless Steel Concrete Anchor Bolts Marine Hardware](https://img.engineeringhardware.com/Anchors-Hot-Sale-Inserts-Drop-in-Expansion-Anchor-Copper-304-Stainless-Steel-Concrete-Anchor-Bolts-Marine-Hardware.webp)](https://engineeringhardware.com/product/anchors-hot-sale-inserts-drop-in-expansion-anchor-copper-304-stainless-steel/) Drop-In & Internal-Thread Anchors ### [Anchors Hot Sale Inserts Drop in Expansion Anchor Copper 304 Stainless Steel Concrete Anchor Bolts Marine Hardware](https://engineeringhardware.com/product/anchors-hot-sale-inserts-drop-in-expansion-anchor-copper-304-stainless-steel/) Steel · ISO, GS, RoHS, CE **US$0.12 – 1.20**MOQ 1,000 pieces [![Standard Zinc Metric Grade 4.8/ 6.8/ 8.8 M6-M20 Drop in Anchor](https://img.engineeringhardware.com/Standard-Zinc-Metric-Grade-4-8-6-8-8-8-M6-M20-Drop-in-Anchor.webp)](https://engineeringhardware.com/product/standard-zinc-metric-grade-4-8-6-8-8-8-m6-m20-drop-in-anchor/) Drop-In & Internal-Thread Anchors ### [Standard Zinc Metric Grade 4.8/ 6.8/ 8.8 M6-M20 Drop in Anchor](https://engineeringhardware.com/product/standard-zinc-metric-grade-4-8-6-8-8-8-m6-m20-drop-in-anchor/) Anchor · 3/16in **US$0.12 – 0.18**MOQ 1,000 kilograms [![Heavy Duty Stainlesss Steel Carbon Steel Zinc Plated Drop in Anchor for Building](https://img.engineeringhardware.com/Heavy-Duty-Stainlesss-Steel-Carbon-Steel-Zinc-Plated-Drop-in-Anchor-for-Building.webp)](https://engineeringhardware.com/product/heavy-duty-stainlesss-steel-carbon-steel-zinc-plated-drop-in-anchor-for-building/) Drop-In & Internal-Thread Anchors ### [Heavy Duty Stainlesss Steel Carbon Steel Zinc Plated Drop in Anchor for Building](https://engineeringhardware.com/product/heavy-duty-stainlesss-steel-carbon-steel-zinc-plated-drop-in-anchor-for-building/) Expansion Anchor · DIN, ANSI, GB, JIS, ASTM **US$0.012 – 0.60**MOQ 1,000 pieces [![ANSI316 M10*40 Stainless Steel Knurled Drop in Anchor, Pipe Internal Anchor](https://img.engineeringhardware.com/ANSI316-M10-40-Stainless-Steel-Knurled-Drop-in-Anchor-Pipe-Internal-Anchor.webp)](https://engineeringhardware.com/product/ansi316-m10-40-stainless-steel-knurled-drop-in-anchor-pipe-internal-anchor/) Drop-In & Internal-Thread Anchors ### [ANSI316 M10*40 Stainless Steel Knurled Drop in Anchor, Pipe Internal Anchor](https://engineeringhardware.com/product/ansi316-m10-40-stainless-steel-knurled-drop-in-anchor-pipe-internal-anchor/) Fasteners · DIN,ANSI,JIS,ASTM, Non-Standard **US$0.12 – 0.36**MOQ 10,000 pieces [![Stainless Steel 306 316 M6-M20 Drop in Expansion Anchor Bolt](https://img.engineeringhardware.com/Stainless-Steel-306-316-M6-M20-Drop-in-Expansion-Anchor-Bolt.webp)](https://engineeringhardware.com/product/stainless-steel-306-316-m6-m20-drop-in-expansion-anchor-bolt/) Drop-In & Internal-Thread Anchors ### [Stainless Steel 306 316 M6-M20 Drop in Expansion Anchor Bolt](https://engineeringhardware.com/product/stainless-steel-306-316-m6-m20-drop-in-expansion-anchor-bolt/) Expansion Anchor Bolt, Non-Standard · DIN, ANSI **US$0.006 – 0.036**MOQ 10,000 pieces [![M10 Zinc Plated Carbon Steel Concrete Knurled Internal Forced Expansion Screw Bolts](https://img.engineeringhardware.com/M10-Zinc-Plated-Carbon-Steel-Concrete-Knurled-Internal-Forced-Expansion-Screw-Bolts.webp)](https://engineeringhardware.com/product/m10-zinc-plated-carbon-steel-concrete-knurled-internal-forced-expansion-screw-bolts/) Drop-In & Internal-Thread Anchors ### [M10 Zinc Plated Carbon Steel Concrete Knurled Internal Forced Expansion Screw Bolts](https://engineeringhardware.com/product/m10-zinc-plated-carbon-steel-concrete-knurled-internal-forced-expansion-screw-bolts/) Drop-in Anchor · Carbon Steel **US$0.06 – 6.00**MOQ 1 piece [View all Drop-In & Internal-Thread Anchors →](https://engineeringhardware.com/fastener-products/anchors-construction-fixings/drop-in-internal-thread-anchors/) [Full product catalog](https://engineeringhardware.com/products/) ## How to Specify Drop-In Anchors (Internally Threaded) for Your Application - **Size:** Match the nominal size to the mating thread or hole. This product spans M6–M16; 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 (displacement-controlled anchor). Quoting the standard on your order guarantees interchangeable dimensions between suppliers. ## Where Drop-In Anchors (Internally Threaded) 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 drop-in anchors (internally threaded) outside the standard range? A non-standard anchor & concrete fixing is quoted from the drawing; where one already exists in the catalog, the special is usually a variation on its tooling. 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 M6 Drop-In Anchors (Internally Threaded) to Trade series (displacement-controlled anchor). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Drill hole diameter (mm):** 8 - **Embedment depth (mm):** 25 - **Body length (mm):** 25 - **Setting tool required:** Yes - **Flush with surface:** Yes - **Material:** Zinc plated steel - **Base material:** Concrete C20/25 and above ## Dimensions & Specifications (Trade series (displacement-controlled anchor)) | Internal thread | Drill hole diameter (mm) | Embedment depth (mm) | Body length (mm) | Setting tool required | Flush with surface | Material | Base material | | --- | --- | --- | --- | --- | --- | --- | --- | | M6 | 8 | 25 | 25 | Yes | Yes | Zinc plated steel | Concrete C20/25 and above | | M8 | 10 | 30 | 30 | Yes | Yes | Zinc plated steel | Concrete C20/25 and above | | M10 | 12 | 40 | 40 | Yes | Yes | Zinc plated steel | Concrete C20/25 and above | | M12 | 16 | 50 | 50 | Yes | Yes | Zinc plated steel | Concrete C20/25 and above | | M16 | 20 | 65 | 65 | Yes | Yes | Zinc plated steel | Concrete C20/25 and above | 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 Drop-In Anchors (Internally Threaded) used for? Providing a flush, internally threaded fixing point in concrete so the bolt — and the fixture with it — can be removed and replaced without disturbing the anchor. They are supplied to Trade series (displacement-controlled anchor). ### Which industries use Drop-In Anchors (Internally Threaded)? They are commonly specified in structural fixing to concrete, building services and plant & machine installation, among other sectors. ### How do I choose the right size of Drop-In Anchors (Internally Threaded)? Match the nominal size to the mating thread or hole. This product is available from M6 to M16; the full dimension table on this page lists each size. ### What material should Drop-In Anchors (Internally Threaded) 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 Drop-In Anchors (Internally Threaded) 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: [Drop-In Anchors (Internally Threaded) — specifications & sizes](https://engineeringhardware.com/fastener/drop-in-anchors/) ### Drop-In Anchors (Internally Threaded) Specification Guides ### Related Fastener Applications