Manufactured to JIS B 1558 / ISO 9628, UC300 Series Insert Bearings are insert bearings & housed units 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 UC300 Series Insert Bearings?
UC300 Series Insert Bearings are insert bearings & housed units defined by JIS B 1558 / ISO 9628. 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
The insert bearing is through-hardened GCr15 / 100Cr6 with a spherical outer ring. The housing is a separate material decision: grey cast iron for general industrial duty, ductile iron where shock is expected, pressed steel for light duty and low mass, thermoplastic or 304 stainless for washdown and food service. Seals are normally nitrile; specify FKM above 100 degrees C.
Typical Applications
Conveyors, agricultural equipment, fans and general OEM machinery, bolted straight to a frame with no machined housing bore. Read the full application guide for UC300 Series Insert Bearings →
Pricing
UC300 Series Insert Bearings are supplied to order. Pricing starts from approximately US$9.00 per piece for standard shaft sizes with a grey cast iron housing and setscrew locking; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.
Specifying the UC300 Series Insert Bearings
Most enquiries start from a shaft diameter rather than from a designation. The bore pages take one size at a time — 30 mm bore, 35 mm bore, 40 mm bore and 45 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. GCr15 Bearing Steel, Martensitic Stainless 440C and Cast Iron set out the trade-off for each grade in the same terms.
For the machines and duties this type is actually specified for, see where uc300 series insert 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.