Manufactured to ISO 15 / GB/T 288 / DIN 635-2, 21300 Series Spherical Roller Bearings are spherical roller 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 21300 Series Spherical Roller Bearings?
21300 Series Spherical Roller Bearings are spherical roller bearings defined by ISO 15 / GB/T 288 / DIN 635-2. 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 barrel rollers are through-hardened GCr15 / 100Cr6, or case-hardened steel in the larger bores. Cages are pressed steel, machined brass or, in the large sizes, a pin-type cage. This family is heat stabilized as standard for operation to 200 degrees C, which matters because it is normally the bearing in the hottest and dirtiest position on the machine.
Typical Applications
Vibrating screens, crushers, paper machines, continuous casting lines and wind turbine main shafts — the heaviest loads, with shaft deflection taken up by the bearing. Read the full application guide for 21300 Series Spherical Roller Bearings →
Pricing
21300 Series Spherical Roller Bearings are supplied to order. Pricing starts from approximately US$30.00 per piece for standard bore sizes in bearing steel, cylindrical bore, C3 clearance; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.
Specifying the 21300 Series Spherical Roller Bearings
Most enquiries start from a shaft diameter rather than from a designation. The bore pages take one size at a time — 35 mm bore, 40 mm bore, 45 mm bore and 50 mm bore — and carry the boundary dimensions for that bore together with the shaft and housing tolerances that go with it.
Material changes what this bearing tolerates far more than it changes what it costs. Case-Hardened 20CrMnTi, Pressed Steel Cage and Polyamide Cage set out the trade-off for each grade in the same terms.
The dimensions above are fixed by ISO 15 and ISO 5753-1 — 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 21300 series spherical roller 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.