--- title: "What Are Retaining Ring (Circlip) Used For?" description: "Retaining Ring (Circlip) are used for axial retention of components on shafts and in bores. Catalogued 8 mm to 100 mm." url: https://engineeringhardware.com/applications/cad-svg-147-ring/ source: Engineering Hardware & Fasteners --- # What Are Retaining Ring (Circlip) Used For? Retaining Rings · ISO / DIN · Application guide Typical applications, the industries that specify retaining ring (circlip), and how to choose the right size, material and finish for the joint. Retaining Ring (Circlip) are used for axial retention of components on shafts and in bores. They are manufactured to ISO / DIN, and selection is driven by the shaft / bore diameter, the fit and tolerance the assembly requires, and the service environment. - **Primary duty:** Axial retention of components on shafts and in bores - **Governing standard:** ISO / DIN - **Shaft / bore diameter range:** 8 mm to 100 mm - **Category:** Retaining Rings Application notes are general engineering guidance. Verify the property class and any approval requirement against your own design calculation. ![What Are Retaining Ring (Circlip) Used For? application image](https://engineeringhardware.com/wp-content/uploads/2026/06/Retaining-Ring-Circlip-—-ISO-DIN-Series-147-—-ISO-DIN.webp) Retaining Ring (Circlip) are used primarily for axial retention of components on shafts and in bores. 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 ISO / DIN. Stocked across roughly 8 mm to 100 mm, they cover general to heavy-duty work. ## Typical Applications for Retaining Ring (Circlip) — ISO / DIN (Series 149) The most common settings where these are specified: - **Hydraulic & pneumatic:** holding pistons and seals in bores. - **Automotive driveline:** axial location on rotating shafts. - **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 Retaining Ring (Circlip) — ISO / DIN (Series 149) for Your Application - **Size:** Select on nominal diameter, then on the hole tolerance and fit class — the fit, not the diameter alone, determines whether the part locates or slips. This product spans 8 mm–100 mm; check the full table below for the exact dimensions of each size. - **Groove fit:** Specify to the shaft or bore groove diameter; the ring must seat fully in the groove to carry the thrust load. - **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 is a trade-series article rather than one covered by a published dimensional standard, so dimensions can differ between manufacturers. Quote the dimensions you need — or the part you are replacing — rather than a standard number. ## Installation & Assembly Practice - Use the correct circlip pliers for the ring size; over-spreading a ring permanently reduces its retention. - Check the ring is fully seated in the groove around its whole circumference before loading the assembly. ## Common Selection Mistakes with Retaining Ring (Circlip) — ISO / DIN (Series 149) - Machining the groove to the shaft tolerance instead of the groove dimensions in the ring standard. - Loading a standard ring axially beyond the groove rating instead of moving to a heavy-duty section ring. ## Where Retaining Ring (Circlip) — ISO / DIN (Series 149) Are Not the Right Choice Not for heavy axial thrust beyond the groove rating, and not where the groove cannot be machined to spec. Custom manufacturing · Made to drawing ## Need a retaining ring (circlip) outside the standard range? Groove dimensions, thickness, material temper and finish decide the part; the ring is made to the groove, so the groove drawing is what is actually needed. Made by stamping. Minimum order from 2,000 pieces; samples within 7 days of drawing approval. [Custom retaining ring manufacturing](https://engineeringhardware.com/custom/rings/)[Send a drawing](https://engineeringhardware.com/custom/rings/#rfq) ## Technical Drawing Dimensioned line drawing of 8 Retaining Ring (Circlip) — ISO / DIN (Series 149). Side view and top view, drawn to the dimensions in the table below and redrawn for any size selected. - **Ring free diameter (mm):** 7.4 - **Groove diameter (mm):** per DIN 471 - confirm for this size - **Ring thickness s (mm):** 0.8 - **Type:** External ## Dimensions & Specifications (ISO / DIN) | Nominal shaft diameter (mm) | Ring free diameter (mm) | Groove diameter (mm) | Ring thickness s (mm) | Type | Reference standard | | --- | --- | --- | --- | --- | --- | | 8 | 7.4 | per DIN 471 - confirm for this size | 0.8 | External | DIN 471 / GB/T 894 | | 10 | 9.3 | per DIN 471 - confirm for this size | 1.0 | External | DIN 471 / GB/T 894 | | 12 | 11.1 | per DIN 471 - confirm for this size | 1.0 | External | DIN 471 / GB/T 894 | | 16 | 15.0 | per DIN 471 - confirm for this size | 1.0 | External | DIN 471 / GB/T 894 | | 20 | 19.0 | per DIN 471 - confirm for this size | 1.2 | External | DIN 471 / GB/T 894 | | 25 | 23.9 | per DIN 471 - confirm for this size | 1.2 | External | DIN 471 / GB/T 894 | | 30 | 28.9 | per DIN 471 - confirm for this size | 1.5 | External | DIN 471 / GB/T 894 | | 40 | 38.5 | per DIN 471 - confirm for this size | 1.75 | External | DIN 471 / GB/T 894 | | 50 | 48.5 | per DIN 471 - confirm for this size | 2.0 | External | DIN 471 / GB/T 894 | | 60 | 58.3 | per DIN 471 - confirm for this size | 2.0 | External | DIN 471 / GB/T 894 | | 80 | 78.0 | per DIN 471 - confirm for this size | 2.5 | External | DIN 471 / GB/T 894 | | 100 | 98.0 | per DIN 471 - confirm for this size | 3.0 | External | DIN 471 / GB/T 894 | 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 Retaining Ring (Circlip) — ISO / DIN (Series 149) 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 Retaining Ring (Circlip) — ISO / DIN (Series 149) made to a recognized standard? Yes — they are manufactured to ISO / DIN, so dimensions are interchangeable between suppliers when you quote the standard on your order. ### What are Retaining Ring (Circlip) — ISO / DIN (Series 149) used for? Axial retention of components on shafts and in bores. They are supplied to ISO / DIN. ### Which industries use Retaining Ring (Circlip) — ISO / DIN (Series 149)? They are commonly specified in hydraulic & pneumatic, automotive driveline and general machine building, among other sectors. ### Can I get a quote for Retaining Ring (Circlip) — ISO / DIN (Series 149) 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: [Retaining Ring (Circlip) — ISO / DIN (Series 149) — specifications & sizes](https://engineeringhardware.com/fastener/cad-svg-149-ring/) ### Retaining Ring (Circlip) — ISO / DIN (Series 149) Specification Guides ### Related Fastener Applications