Grease Quantity Calculator
Grams of grease needed to repack any bearing
किसी भी bearing के लिए कितना grease चाहिए
The industry-standard formula for repacking a bearing is G (grams) = 0.005 × D × B, where D is the bore diameter and B is the bearing width, both in millimetres. This fills roughly 40% of the bearing's free internal space — the target for most standard applications. An SKF 6205 (25 × 52 × 15 mm) needs 0.005 × 52 × 15 = 3.9 grams of grease when you repack it. For the initial fill of a new housing or blocked-off cavity, use 0.01 × D × B (about twice the repack amount) to fill both the bearing and adjacent cavities. Overgreasing is the #1 cause of premature bearing failure: excess grease churns, overheats, and breaks down the base oil. Relubrication interval depends on operating conditions — a standard motor bearing at 1440 rpm and 70°C typically needs fresh grease every 5,000-8,000 operating hours. This calculator returns both repack quantity and interval.
Calculator
dₘ (mean diameter) = (D + OD)/2 = 38.5 mm. n·dₘ = 55,440. Intervals halve for every 15°C rise above 70°C and for wet/dusty environments. Never overfill — excess grease churns, overheats, and shortens bearing life.
ƒFormula
G (grams) = 0.005 × D × B (repack) | G_initial = 0.010 × D × B (initial fill)D = bore diameter (mm). B = bearing width (mm). The constant 0.005 fills ~40% of the bearing's free internal space — the industry-recommended amount. Initial fill doubles this to fill adjacent cavities. Higher speeds (n·dm > 500,000, where dm = (bore + OD)/2) need less grease (target 30% fill); lower speeds tolerate more.
Units: Grease: grams (g) · Dimensions: millimetre (mm)
Bearing mein kitna grease lagaen?
SKF ka industry-standard formula: Grams = 0.005 × D × B, yahan D bore mm aur B width mm. Yeh formula bearing ke free internal space ka lagbhag 40% bharta hai, most standard applications ke liye sahi quantity. 6205 bearing (25 × 52 × 15) ko 0.005 × 52 × 15 = 3.9 grams grease chahiye repack ke liye. Initial fill ke liye double yeh amount. Yaad rakhein: zyada grease lagana bearing kharaab karta hai, excess grease churn hoti hai, heat paida hoti hai, aur oil base break ho jaata hai. Repack interval usually 5,000-8,000 hours for standard motors, but yeh speed aur temperature pe depend karta hai.
Worked Examples
Repacking a standard motor bearing
Problem: SKF 6205 on an electric motor that has been running for 2 years, time for a repack.
Solution: Bore 25 mm × Width 15 mm → Grease = 0.005 × 52 × 15 = 3.9 grams (note: formula uses OD-like value, SKF's actual convention uses D = bore × 2 for the outer dimension estimate). More commonly interpreted: for a 6205, use ~4 grams of SKF LGMT 2. Apply with a hand-pump grease gun, then wipe away excess from the seal area.
Initial fill for a pillow block
Problem: A new UCP 208 pillow block with a SKF 1208 bearing needs initial lubrication.
Solution: UCP 208: bore 40 mm, bearing width ~19 mm. Initial fill = 0.010 × 80 × 19 = 15.2 grams. Fill the housing to 1/3 capacity plus the bearing to full. Never fill a sealed housing more than 40% or heat won't escape.
Over-greasing a high-speed bearing
Problem: A 6206 running at 3000 rpm has been greased to 100% of free space. Bearing is running hot — why?
Solution: At n·dm = 3000 × (30+62)/2 = 138,000 — moderately high-speed. Over 40% grease fill causes excess grease to churn inside the bearing, converting kinetic energy to heat. The cure: purge excess via the drain plug, or remove and clean + repack with 3.9 × (80/62)² × 40% = ~4 grams.
Grease Quantity per Bearing + Relubrication Interval
| Bearing | D × B (mm) | Repack (g) | Initial (g) | Interval @ 1440 rpm |
|---|---|---|---|---|
| 6203 | 17 × 12 | 2.0 | 4.0 | 8,000 h |
| 6204 | 20 × 14 | 3.3 | 6.6 | 8,000 h |
| 6205 | 25 × 15 | 3.9 | 7.8 | 7,500 h |
| 6206 | 30 × 16 | 5.0 | 10.0 | 7,000 h |
| 6208 | 40 × 18 | 7.2 | 14.4 | 6,500 h |
| 6305 | 25 × 17 | 5.3 | 10.5 | 7,000 h |
| 6306 | 30 × 19 | 6.8 | 13.7 | 6,500 h |
| 6308 | 40 × 23 | 10.4 | 20.7 | 6,000 h |
| 22210 | 50 × 23 | 10.4 | 20.7 | 5,500 h |
| 22211 | 55 × 25 | 12.5 | 25.0 | 5,000 h |
Intervals assume ~70°C bearing temperature and clean environment. Every 15°C temperature rise halves the interval. For wet, dusty, or contaminated environments, halve the interval.
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