The principal dimensions are 30x72x19 mm at a weight of 0.345 kg; the further technical details are listed in the specification table. This variant features a contact seal and greatly increased radial clearance (C4). The deep groove ball bearing is the most widely built rolling bearing type, and the reason is how little it asks: it carries radial load, supports moderate axial load in both directions, and demands little of the surrounding design.
The deep, closely conforming raceway grooves in the inner and outer ring capture the balls positively, so the bearing takes radial load and moderate axial load in both directions without a second bearing position to oppose it. Because the ball touches the raceway at a point, friction and heat stay low — the precondition for high speeds and for grease-for-life designs.
The limits follow from that same geometry: the small contact area caps load capacity against a roller bearing of equal size, and the bearing tolerates misalignment within narrow limits only, since angular error transfers straight into the raceway grooves. Seats in shaft and housing must therefore be aligned and geometrically accurate; where shaft deflection is expected, a self-aligning type belongs in that position.
The contact seal bears against its counterface and closes the rolling chamber against dust, splash water and wash-out; in return it raises frictional torque and limits permissible speed. Rings and rolling elements are made of through-hardened standard bearing steel. The strongly increased radial clearance is intended for pronounced temperature differences between the rings or for very tight fits; without those conditions the bearing runs with unnecessary play.
ManufacturerNSK
Bearing typeDeep-groove ball bearings
Bore d30 mm
Outer Ø D72 mm
Width B19 mm
Weight0.345 kg
Sealscontact seal on one side
Clearanceradial internal clearance much greater than normal
Cagepressed steel cage
Materialstandard bearing steel
Tolerancetolerance class P0/PN (ABEC 1)
Bore typecylindrical bore
€5.47/ pc
incl. VAT, plus shipping · price drops with quantity
In stock
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In stock · ships via DPD, UPS or Deutsche Post
QtyUnit priceDisc.
1 – 4€5.47—
5 – 9€5.31−3 %
10 – 24€5.20−5 %
25 – 49€5.03−8 %
50 – 99€4.92−10 %
4 more for −3% volume discount
From 100 pcs: price and lead time on request – subject to review.
Total (1 pc)€5.47
NSK 6306 DUC4 Kugellager (30x72x19)
— 30 x 72 x 19 mm
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✓Purchase on invoice – first order paid before dispatch, then 14-day terms for approved business customers
Same dimensions means the same bearing type and matching main dimensions (d × D × B). Sealing, cage, internal clearance and execution (e.g. material, precision, grease fill) are encoded in the suffix and may differ — please check before ordering. Equivalent additionally means the same sealing, internal clearance and tolerance class; the cage and other suffix features (e.g. lubrication groove) may differ.
