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CUSTOM / 08 MAX
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| Parameter | NSK680840 × 52 × 7 mm | KOYO680840 × 52 × 7 mm | NACHI680840 × 52 × 7 mm | EZO680840 × 52 × 7 mm |
|---|---|---|---|---|
| Comparable specifications | ||||
| Brand | NSK | KOYO | NACHI | EZO |
| Designation | 6808 | 6808 | 6808 | 6808 |
| Product family | Single row deep groove ball bearings | Single-row / Open type | Deep groove ball bearing | Thin-Section Ball Bearing |
| Detailed type | Deep groove ball bearings | Deep groove ball bearings | Deep groove ball bearings | Deep groove ball bearings |
| Bore diameterd | 40 mm | 40 mm | 40 mm | 40 mm |
| Outside diameterD | 52 mm | 52 mm | 52 mm | 52 mm |
| WidthB | 7 mm | 7 mm | 7 mm | 7 mm |
| Basic dynamic load ratingC | 7 kN | 6.15 kN | 6.2 kN | 4.93 kN |
| Basic static load ratingC0 | 5.55 kN | 4.2 kN | 4.15 kN | 4.18 kN |
| Fatigue load limitPu | — | 0.18 kN | — | — |
| Limiting speednG | — | 12000 r/min | — | — |
| Mass≈m | 0.031 kg | 0.033 kg | 0.033 kg | 0.0289 kg |
| Sealing | Open | Open | Open | Open (no closure suffix in this catalogue marking) |
| Bearing material | — | — | — | High-carbon chromium bearing steel |
| Boundary dimensions | ||||
| Bearing widthB | 7 mm | — | 7 mm | — |
| Outer diameterD | — | — | — | 52 mm |
| Minimum bearing chamferr min. | 0.3 mm | — | 0.3 mm | — |
| Outer diameterD | — | — | — | 2.0472 inch |
| Inner ring widthB | — | — | — | 7 mm |
| Inner ring widthB | — | — | — | 0.2756 inch |
| Outer ring widthC | — | — | — | 7 mm |
| Outer ring widthC | — | — | — | 0.2756 inch |
| Inner ring chamfer dimensionr si min | — | — | — | 0.3 mm |
| Inner ring chamfer dimensionr si min | — | — | — | 0.0118 inch |
| Outer ring chamfer dimensionr se min | — | — | — | 0.3 mm |
| Outer ring chamfer dimensionr se min | — | — | — | 0.0118 inch |
| Classification | ||||
| Official Category Path | — | Deep groove ball bearings - Single-row - Open type | — | — |
| Official Classification 1 | — | Deep groove ball bearings / Single-row / Open type | — | — |
| Construction | ||||
| Closure arrangement | — | — | Open | — |
| Listed closure suffix | — | — | None (open type) | — |
| Catalogue closure construction | Open | — | — | — |
| Closure interpretation | — | — | — | Open (no closure suffix in this catalogue marking) |
| Material interpretation | — | — | — | High-carbon chromium bearing steel |
| Equivalent-load factors | ||||
| Catalogue load calculation factorf0 | — | — | 16.2 | — |
| Load ratings | ||||
| Basic dynamic radial load ratingCr | 7000 N | — | 6200 N | — |
| Basic static radial load ratingC0r | 5550 N | — | 4150 N | — |
| Equivalent-load calculation factorf0 | 17 | — | — | — |
| Lubrication-qualified speed | ||||
| Limiting speed with grease | 12000 r/min | — | — | — |
| Limiting speed with oil (open bearing) | 14000 r/min | — | — | — |
| Limiting speed with grease (open) | — | — | 12000 r/min | — |
| Limiting speed with oil (open) | — | — | 14000 r/min | — |
| Catalogue limiting speed (grease) | — | — | — | 12000 r/min |
| Catalogue limiting speed (oil) | — | — | — | 14000 r/min |
| Manufacturer Identity | ||||
| Official Class Key | — | 010-010-010 | — | — |
| Mounting dimensions | ||||
| Minimum shaft shoulder diameterda min. | 42 mm | — | 42 mm | — |
| Maximum shaft shoulder diameterda max. | 42 mm | — | — | — |
| Maximum housing shoulder diameterDa max. | 50 mm | — | 50 mm | — |
| Maximum adjacent fillet radiusra max. | — | — | 0.3 mm | — |
| Maximum shaft or housing fillet radiusra max. | 0.3 mm | — | — | — |
| Adjacent mounting dimension (da min)da min | — | — | — | 49 mm |
| Adjacent mounting dimension (da min)da min | — | — | — | 1.9291 inch |
| Adjacent mounting dimension (da max)da max | — | — | — | 50 mm |
| Adjacent mounting dimension (da max)da max | — | — | — | 1.9685 inch |
| Adjacent mounting dimension (r asi max)r asi max | — | — | — | 0.3 mm |
| Adjacent mounting dimension (r asi max)r asi max | — | — | — | 0.0118 inch |
| Adjacent mounting dimension (r ase max)r ase max | — | — | — | 0.3 mm |
| Adjacent mounting dimension (r ase max)r ase max | — | — | — | 0.0118 inch |
| Reference mass | ||||
| Catalogue row mass (variants not individually specified) | — | — | 0.033 kg | — |
| Approximate catalogue mass (open reference) | 0.031 kg | — | — | — |
| Reference mass | — | — | — | 28.9 g |
| Rolling elements | ||||
| Ball diameterDw | — | — | — | 3.5 mm |
| Ball quantityZ | — | — | — | 21 |
| Technical Data | ||||
| d | — | 52 mm | — | — |
| B | — | 7 mm | — | — |
| R(Min.) | — | 0.3 mm | — | — |
| Basic Load Ratings : Cr | — | 6.15 kN | — | — |
| Basic Load Ratings : C0R | — | 4.20 kN | — | — |
| Fatigue Load Limit : Cu | — | 0.180 kN | — | — |
| Factor : F0 | — | 16.3 | — | — |
| Limiting Speeds(Grease Lub.) | — | 12000 min-1 | — | — |
| Limiting Speeds(Oil Lub.) | — | 14000 min-1 | — | — |
| Da(Min.) | — | 42 mm | — | — |
| Da(Max.) | — | 50 mm | — | — |
| Ra(Max.) | — | 0.3 mm | — | — |
| Mass(Refer.) | — | 0.033 kg | — | — |
Independent reference comparison based on the manufacturer data currently loaded. Always verify current limits, tolerances and suffix definitions with the official source before engineering selection.