External circlip 8 mm
DIN 471 External circlip 8 mm - Carbon Spring Steel
8 mm
shaft
Technical specification
| Standard | DIN 471 |
|---|---|
| Type | External circlips |
| Nominal size | 8 mm shaft |
| Measured on | shaft |
| Material | Carbon spring steel |
| Pack quantity | 25 pieces |
| Axial SKU | AX-471-8-CS-25 |
| Availability | Available to order |
£5.05
Pack of 25 · No VAT charged
Available to order
25 pieces · £5.05
Sold by the pack of 25. No VAT charged on any order.
Need a size that is not listed? Ask the trade desk.
About this part
A 8 mm external circlip is the ring for a 8 mm shaft. It is expanded to pass over the shaft and relaxes into a groove machined around it, and the part standing proud of the shaft forms a removable shoulder holding a bearing, gear or pulley against axial load. The 8 mm is the shaft diameter, not the diameter of the ring.
DIN 471 fixes the groove for this size: 7.6 mm groove diameter, 0.9 mm wide, taking a ring 0.8 mm thick, with at least 0.6 mm between the groove and the end of the shaft. Those are the numbers to machine to and to check an existing groove against — if what you measure disagrees, either the surface is wrong or the part is not to DIN 471.
The neighbouring sizes are 7 mm and 9 mm. Reach for one of those only because you measured the shaft and got that number — not because this ring feels tight or slack in the hand. A ring that seems slightly loose is usually a worn groove rather than a wrong size, and going up a size to take up the slack puts a ring in a groove it was never dimensioned for. If your measurement falls between 7 mm and 8 mm, clean the shaft and measure again before choosing: dirt and old paint read as diameter.
Groove dimensions to DIN 471
Fixed by the standard, not by us. Machine the groove to these and the ring seats correctly; check them against your drawing before cutting.
Source: Aspen Fasteners and Springmasters Ltd, which do not agree on this size — see below.
| Groove diameter d2 | 7.6 mm |
|---|---|
| Groove width m | 0.9 mm |
| Ring thickness s | 0.8 mm |
| Min. edge margin n | 0.6 mm |
Our sources do not agree on the groove width for this size
Springmasters' product page for the 8 mm ring gives a groove width of 1.1 mm where both of our references give 0.9 mm. Every other figure for the size agrees, including the 0.8 mm ring thickness — and a 1.1 mm groove is the value the standard gives for 9 mm, which is what a row read one line low would produce. We publish 0.9 mm because two independent sources give it and one does not, but the figure is not settled: measure the groove, or take it from the standard, before machining to either number.
Edge margin is the minimum distance from the groove to the end of the shaft or bore. Cutting closer removes the material that resists shearing at full load. Full DIN 471 table.
Check the specification before ordering
Retaining rings are dimension-critical. Confirm the groove diameter, groove width and ring thickness against the applicable standard for your application. Safety-critical assemblies need independent engineering verification.
Before you order
- How to measure for a circlip — measure the shaft, not the old ring
- DIN 471 explained — what the nominal size refers to
- Fitting and removing circlips — pliers, seating and safety
shaft circlips, external retaining rings, external snap rings, Seeger rings, lock rings — all the same part, listed here by the shaft it fits.
Photographs show a representative part from the DIN 471 range. Dimensions are governed by the standard, not by the photograph.
Nearby sizes
Same family and standard, adjacent nominal sizes.