Clips, Connectors & Rings

What are clips, connectors and rings?

Clips, connectors and rings are small retaining fasteners used to hold parts in position on shafts, in bores, and in assemblies. The most common types are circlips and snap rings, which fit into grooves cut in a shaft or a bore to create a shoulder that stops bearings, gears, pulleys, pins, and other components from sliding out of place. They are simple, compact, and reliable, and they allow parts to be fitted and removed quickly without the need for threads, nuts, or machined shoulders.

Clips, connectors and rings are made from spring steel, so they can be expanded or compressed to fit over a shaft or into a bore, then spring back into their groove to hold securely.

They are usually described by:

• Shaft or bore size - the diameter of the shaft or bore the ring is designed to fit, such as a 16 mm shaft or a 39 mm bore
• Type - such as external circlip, internal circlip, snap ring, or E-clip
• Un-sprung diameter - the size of the ring in its free state, before it is fitted
• Thickness - the thickness of the ring, which must suit the groove width
• Material and finish - such as phosphated spring steel or stainless steel
• Standard - such as DIN 471 for external circlips or DIN 472 for internal circlips

For example, an external circlip for a 16 mm shaft fits into a groove on a 16 mm shaft, while a snap ring to suit a 39 mm bore fits into a groove inside a 39 mm hole.

Key features:

• Secure axial retention - holds bearings, gears, and parts in place on shafts and in bores
• Compact - takes up very little space compared with nuts, collars, or shoulders
• Quick to fit and remove - installed and removed with simple tools such as circlip pliers
• Reduces machining - a simple groove replaces threads, shoulders, or extra components
• Spring steel construction - springs firmly into the groove for a secure hold
• Range of sizes - for small shafts and bores through to large industrial assemblies
• Standardised - many rings follow DIN standards for consistent sizes and groove dimensions

In simple terms, clips, connectors and rings are spring steel retainers that clip into grooves to stop parts sliding along shafts or out of bores.

Why are clips, connectors and rings essential?

Clips, connectors and rings are essential because many components need to be held in a fixed position along a shaft or inside a housing. Without retention, bearings can walk out of housings, gears and pulleys can slide along shafts, and pins can work loose. Circlips and snap rings provide a simple, low-cost, and space-saving way to keep parts exactly where they need to be, while still allowing them to be removed for maintenance.

Their main benefits are:

• Keeps parts in position - stops bearings, gears, pulleys, and pins moving axially
• Saves space - ideal for compact assemblies where nuts and collars will not fit
• Simplifies design - reduces the need for shoulders, threads, and extra fixings
• Quick assembly - parts can be fitted and secured in seconds
• Easy maintenance - rings can be removed with the right tools for repairs
• Reliable - spring steel holds firmly in the groove under load and vibration
• Cost-effective - inexpensive components that protect more valuable parts

Clips, connectors and rings are used across a wide range of industries and applications, including:

• Bearing assemblies - retaining bearings on shafts and in housings
• Gearboxes and drives - locating gears, shafts, and spacers
• Electric motors - holding bearings and rotors in place
• Automotive and transport - drive shafts, suspension, brakes, and transmissions
• Agricultural machinery - pivots, shafts, linkages, and pulleys
• Hydraulic and pneumatic cylinders - retaining seals, end caps, and pistons
• Power tools and appliances - holding shafts, gears, and moving parts
• Industrial machinery - conveyors, pumps, fans, and production equipment
• Bikes, toys, and hobby projects - small shafts and pivots

The main types of clips, connectors and rings

Clips, connectors and rings are usually grouped by where they fit and how they are designed.

Circlips:

• External circlips - fit into a groove on the outside of a shaft. They are opened with circlip pliers, slid over the shaft, and released into the groove. Made to standards such as DIN 471
• Internal circlips - fit into a groove inside a bore or housing. They are squeezed with circlip pliers, inserted into the bore, and released into the groove. Made to standards such as DIN 472
• Heavy duty circlips - thicker circlips for higher axial loads

Snap rings:

• Round wire snap rings - made from round-section spring wire with a gap between the ends. They are sprung into a groove in a shaft or bore without the need for pliers, and are often used to retain bearings and components in housings
• Snap rings for bores - fit into grooves inside bores and housings
• Snap rings for shafts - fit into grooves on the outside of shafts
• Bearing snap rings - fit into a groove on the outer ring of bearings with a snap ring groove, locating the bearing in its housing

Clips:

• E-clips - shaped like the letter E, they push sideways into a groove on a shaft without needing to be slid along it. Ideal for small shafts and quick assembly. Made to standards such as DIN 6799
• Push-on fixes - push onto plain shafts and grip without the need for a groove
• R-clips - spring clips used to secure clevis pins and hitch pins

Connectors:

• Chain connecting links - join and close the ends of roller chains
• Split rings and quick links - used to join chains, cables, and fittings

By material:

• Spring steel - the standard material, usually with a black phosphate or oiled finish for corrosion protection
• Stainless steel - resists rust and corrosion, ideal for wet, marine, and food-processing environments
• Zinc plated spring steel - a bright finish with improved corrosion protection

How to choose the right clips, connectors and rings?

Choosing the right clip or ring means matching it to the shaft or bore, the groove, and the load. Work through these points in order:

• Shaft or bore - decide whether the ring will fit on a shaft or inside a bore, and choose external or internal types accordingly
• Size - choose a ring designed for the exact shaft or bore diameter
• Groove dimensions - check that the groove diameter and width match the ring. Standards such as DIN 471 and DIN 472 set the groove sizes for each ring size
• Type - choose circlips for general retention, round wire snap rings for simple pliers-free fitting, E-clips for small shafts with sideways access, and bearing snap rings for bearings with snap ring grooves
• Load - choose heavy duty circlips or thicker rings for higher axial loads
• Access - choose E-clips where you can only reach the shaft from the side, and circlips where you can slide the ring along the shaft or into the bore
• Removal - consider whether the ring will need to be removed often, and choose a type that suits the tools available
• Material - choose phosphated spring steel for general use, and stainless steel for wet or corrosive environments
• Speed - for high-speed shafts, check that the ring is suitable, as rings can lift out of their grooves at very high speeds
• Quality and brand - choose rings from reputable suppliers for accurate dimensions and consistent spring strength

How to fit clips, connectors and rings

Fitting clips and rings correctly helps them hold securely:

• Clean the groove - remove dirt, burrs, and old grease from the groove
• Use the right tool - use internal or external circlip pliers with tips that fit the lug holes properly. Round wire snap rings can often be fitted by hand or with a small screwdriver
• Do not overstretch - open or close the ring only as much as needed to fit it. Overstretching can permanently deform the ring and weaken its grip
• Seat it fully - make sure the ring sits fully and evenly in the groove all the way around
• Check orientation - some stamped circlips have one sharp edge and one rounded edge. Fit them as recommended by the manufacturer for the best grip
• Check the fit - rotate the ring in the groove with a screwdriver to confirm it is seated, then check the retained part cannot move
• Use new rings - replace rings that have been removed, as they can lose their spring tension

FAQ - All you need to know about clips, connectors and rings

What is a circlip?

A circlip is a spring steel retaining ring that fits into a groove on a shaft or inside a bore. It creates a shoulder that stops parts, such as bearings and gears, sliding out of place.

What is the difference between internal and external circlips?

External circlips fit into a groove on the outside of a shaft. Internal circlips fit into a groove inside a bore or housing.

What is a snap ring?

A snap ring is a retaining ring, often made from round spring wire, that snaps into a groove in a shaft or bore. Round wire snap rings can usually be fitted without pliers.

What does un-sprung diameter mean?

The un-sprung diameter is the size of the ring in its free state, before it is fitted. External circlips are slightly smaller than the shaft when un-sprung, so they grip the groove. Internal circlips are slightly larger than the bore, so they press outwards into the groove.

What do DIN 471 and DIN 472 mean?

DIN 471 is the standard for external circlips for shafts, and DIN 472 is the standard for internal circlips for bores. They set the dimensions of the rings and their grooves.

How do I know what size circlip I need?

Measure the diameter of the shaft or bore where the ring will fit, not the groove. Choose a circlip made for that shaft or bore size, and check the groove width suits the ring thickness.

What is an E-clip?

An E-clip is a retaining clip shaped like the letter E. It is pushed sideways into a groove on a shaft, making it ideal for small shafts and assemblies with limited access.

What tools do I need to fit circlips?

Use circlip pliers, with external pliers for shaft circlips and internal pliers for bore circlips. Choose pliers with tips that fit the holes in the circlip lugs.

Can I reuse circlips?

It is best to fit new circlips, especially in critical or high-load applications. Removing a circlip can overstretch it and reduce its grip.

Why did my circlip come out?

Common causes include a worn or wrongly sized groove, an overstretched or reused ring, the wrong ring size, excessive axial load, or very high shaft speeds. Check the groove and fit a new ring of the correct size.

Can I use stainless steel circlips?

Yes. Stainless steel circlips resist rust and corrosion, making them ideal for wet, marine, outdoor, and food-processing environments.