R Series Inch Ball Bearings (ABEC / ANSI-ABMA 12.1) are ball bearings. The full size table is below, followed by the material and cage options, how the bearing is located on the shaft and in the housing, and where the type is and is not the right choice.
What Are R Series Inch Ball Bearings?
R Series Inch Ball Bearings are ball bearings defined by ABEC / ANSI-ABMA 12.1. 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 bearing steel — GCr15 / 100Cr6 / SAE 52100 / SUJ2 — at 58 to 64 HRC. AISI 440C martensitic stainless is available where the bearing is washed down or runs wet, at a lower basic dynamic load rating; silicon nitride balls in steel rings raise the speed limit and break the electrical path through the bearing. The cage is a separate decision from the rings and is usually what sets the speed limit: pressed steel as standard, machined brass for shock and high temperature, polyamide PA66 for quiet running and low mass.
Typical Applications
Electric motors, pumps, fans, gearboxes, conveyor idlers and appliances — radial load at speed, with incidental axial load in either direction. Read the full application guide for R Series Inch Ball Bearings →
Pricing
R Series Inch Ball Bearings are supplied to order. Pricing starts from approximately US$1.10 per piece for standard bore sizes in bearing steel, open, shielded or sealed, CN clearance; final pricing depends on size, material, finish and order quantity (MOQ applies). Submit your exact configuration with the quote form above.
Specifying the R Series Inch Ball Bearings
Where the environment decides the specification rather than the load, the material pages are the ones to read: Pressed Steel Cage, Polyamide Cage and Machined Brass Cage. Each states what the grade survives, and what choosing it costs in load capacity or temperature range.
The dimensions above are fixed by 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 r series inch 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.
-
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.
-
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.
-
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.
-
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.