Manufactured to ISO 15 / DIN 628-1 / GB/T 292, 7300B Series Angular Contact Ball Bearings are angular contact ball bearings supplied by Bushing Bearings. Every designation in the series is listed with its boundary dimensions; the interactive half-section drawing redraws itself for whichever size you select.
What Are 7300B Series Angular Contact Ball Bearings?
7300B Series Angular Contact Ball Bearings are angular contact ball bearings defined by ISO 15 / DIN 628-1 / GB/T 292. They are selected by bearing designation and the dimensional characteristics shown below. Material, cage and sealing are specified separately from the designation and are covered further down this page.
Materials & Cage
Rings and balls are through-hardened GCr15 / 100Cr6 at 58 to 64 HRC. Because this bearing is preloaded rather than run with clearance, the cage matters more than usual: pressed steel for general duty, machined brass or phenolic for spindle speeds, PEEK where temperature and chemical exposure rule out phenolic. Hybrid ceramic balls are specified on high-speed spindles for their lower mass and therefore lower centrifugal load on the outer raceway.
Typical Applications
Machine tool spindles, vertical pumps, worm gearboxes and screw drives, where axial load acts in one direction and the bearing is mounted against an opposing one. Read the full application guide for 7300B Series Angular Contact Ball Bearings →
Pricing
7300B Series Angular Contact Ball Bearings are supplied to order. Pricing starts from approximately US$4.80 per piece for standard bore sizes in bearing steel, single bearings at normal preload; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.
Specifying the 7300B Series Angular Contact Ball Bearings
If the shaft is already fixed, go straight to the size: 35 mm bore, 40 mm bore, 45 mm bore and 50 mm bore. Each of those pages repeats only the row that matters for that bore, with the fit and clearance notes underneath it.
Material changes what this bearing tolerates far more than it changes what it costs. GCr15 Bearing Steel, Martensitic Stainless 440C and Silicon Nitride Si3N4 set out the trade-off for each grade in the same terms.
The dimensions above are fixed by ISO 15 and DIN 628 — that is what makes one maker's bearing interchangeable with another's, and it is worth checking which standard a quotation is written to. For the machines and duties this type is actually specified for, see where 7300b series angular contact ball bearings are fitted.
Manufactured in our own plant
This bearing is forged, hardened, ground, superfinished and clearance-set in-house. The stages below are where its tolerance class, its internal clearance and its noise grade are actually decided.
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01 Forging & turning
GCr15 bar and tube is cut, heated and forged into ring blanks, then turned to leave a uniform grinding allowance. Forging rather than machining from solid keeps the grain flow following the raceway, which is the surface that eventually fails.
Blank dimensions and grinding stock checked at set-up and per shift.
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02 Heat treatment
Through-hardening brings GCr15 / 100Cr6 to 58–64 HRC; carburizing case-hardens 20CrMnTi where the section is heavy or the load is shock. Rings are then stabilized so they hold size in service rather than growing in the housing.
Core and surface hardness per lot; retained austenite and dimensional stability to the ordered temperature class.
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03 Raceway grinding
Faces, bore, outer diameter and raceway are ground in sequence on separate machines. This is where the tolerance class is created: P0, P6, P5 or P4 is a grinding outcome, not a sorting outcome.
Bore and outer diameter deviation, raceway roundness and face runout measured to ISO 492 on every setup.
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04 Honing & superfinishing
The ground raceway is honed to remove the grinding lay and bring surface roughness down to a fraction of a micrometre. Raceway finish is what decides whether a lubricant film forms, and therefore what decides bearing life far more than the load rating alone.
Surface roughness Ra and waviness measured per lot.