SIFT BEARING STORE CATALOG

638NSKBall

638 is a NSK ball bearing, bore 8 mm, O.D. 28 mm, width 9 mm, dynamic rating 1,030 lbs. Dimensions, drawing, interchanges and price.

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Bore d8mm
Outside dia. D28mm
Width B9mm
Dynamic Cr1,030lbs
Static C0r443lbs
Limiting speed28,000rpm
Weight0.026kg
Cr / C0r2.33
Mean dia. dm18mm

Original catalogue drawing - NSK catalogue, page 13

638 NSK Ball bearing catalogue drawing

Scanned from the manufacturer catalogue page listing this part number. All part numbers printed on that table share the same drawing.

Scale cross-section

DdBOutside dia. D28 mmBore d8 mmWidth B9 mm

Blue = inner / outer ring, yellow = rolling element. Drawn to scale from this part's own dimensions for selection reference only - not a manufacturing or assembly drawing.

Dimension table (mm / inch)

SymbolDimensionmminch
dBore diameter80.315
DOutside diameter281.1024
BInner-ring / bearing width90.3543
rChamfer (min)0.3050.012

Notes

Weights are given in kg. Load ratings are shown in both the original catalogue units and the converted value (1 N = 0.2248 lbf). Data is provided for selection reference only - confirm against the latest official catalogue before ordering.

Main dimensions

Bore d (mm)8.00
Bore d (in)0.3150
Outside dia. D (mm)28
Outside dia. D (in)1.1024
Width B (mm)9.00
Width B (in)0.3543

Load ratings & speeds

Basic dynamic load rating Cr (lbs)1030
Basic static load rating Cor (lbs)443
Limiting speed - grease (rpm)28,000
Limiting speed - oil (rpm)34,000

Weight

Weight (kg)0.026

Mounting dimensions (fillets / shoulders)

Chamfer r (in)0.012
Shaft shoulder (in)0.394
Housing shoulder (in)1.024

Bearing life (ISO 281 basic rating life)

C / PEquivalent load P (N)L10 (106 rev)L10h at 3,000 rpm
41,14564356
67642161,200
85735122,844
104581,0005,556
153053,37518,750

Basic rating life per ISO 281: L10 = (C/P)3 with C = 4,582 N. Hours = L10 x 106 / (60n). Life-modification factors for lubrication, contamination and temperature (aISO) are not included.

Source & traceability

BrandNSK
Source catalogueNSK inch product catalogue
Catalogue pagep.16 (dimensions) / p.16 (ratings)

Dimensions in inches and millimetres, load ratings in lbs.

Nearby bore sizes

DesignationBrandTypedDB/TDyn. ratingkg
608NSKBall8227741 lbs0.014
628NSKBall8248750 lbs0.015
698NSKBall8196503 lbs0.006
MR128NSKBall8122.50.6 kN0.001
MR148NSKBall8143.50.9 kN0.002
R1810NSKBall7.9412.73.970.6 kN0.001
608-5NSKBall7.9227741 lbs0.014
607NSKBall7196525 lbs0.007

Request a quotation for 638

Send us the quantity you need and we will come back with price and lead time, normally within 24 hours. Equivalent parts from other brands can be quoted at the same time.