RHP7009CTSULP6Super Precision Angular Contact Ball Bearing 45 x 75 x 16 mm, 15° Contact Angle, Light Preload, Universally Ground Single, Phenolic Cage, ABEC 7/9

Product Description

What this part is

A single-row super-precision angular contact ball bearing from RHP’s machine tool spindle range, 45 mm bore × 75 mm outside diameter × 16 mm wide. It sits in ISO dimension series 10 — the 70** table — and combines a 15° contact angle, a light preload setting, universal face control and an outer-ring-guided laminated phenolic cage. This is a spindle bearing, not a general-purpose one: grinding and milling heads, high-speed motorised spindles, precision gearboxes, rotary tables and test rigs, where running accuracy, stiffness and thermal behaviour matter far more than raw load capacity.

Decoding the designation

The carton is printed 7009X2TAULEP3 and the outer ring itself is engraved 7009X2 TAU EP3. This is RHP’s older designation style, in which the construction code sits ahead of the contact angle rather than after it. Read against RHP’s own published designation system:

7 – single-row angular contact ball bearing.
0 – RHP dimension series 0, which is ISO series 10, i.e. the 70** bearing tables.
09 – bore code; from code 04 upwards the code × 5 gives the bore, so 09 × 5 = 45 mm.
U – universal face control. Inner and outer rings are the same width and the face relationships are pre-adjusted at manufacture, so the bearing can be mounted back-to-back, face-to-face or in tandem without altering the preload value.
L – light preload, RHP’s published preload levels being EL extra light, L light, M medium and H heavy. Light is the most commonly specified level and suits applications where loads and speeds are not extreme.
EP3 – precision grade, written in RHP’s older BS292 style. RHP publishes three super-precision grades: P4 (ISO class 4, ABEC 7, BS292 EP7), P3, and P2 (ISO class 2, ABEC 9, BS292 EP9). P3 is defined by RHP as an intermediate grade carrying P2 running-accuracy tolerances with P4 external tolerances. The EP3 marking corresponds to that P3 grade.
X2 and TA – not defined in RHP’s published designation system, which lists neither code. They are left undecoded here rather than guessed at. The cage material and location are stated below from RHP’s published range description and from the bearing itself, not from the TA letters.

Correcting the source data

This listing previously carried two different and mutually exclusive tolerance classes in its own title, P6 and P4. Neither is what the bearing is marked, and one of them is not a grade RHP ever offered in this product line:

P6 (ABEC 3) is wrong and impossible. RHP’s super-precision angular contact range is published only in grades P4, P3 and P2 — ABEC 7 through ABEC 9. An ABEC 3 bearing is a standard-precision product and would not be universally faced or preload-matched at all. The P6 suffix has been removed from the specification and retained only as a cross-reference string for anyone searching the old listing.
P4 (ABEC 7) is close but understates the part. The ring is marked EP3, and RHP grade P3 holds P4 external tolerances but P2 running-accuracy tolerances. For a 45 mm bore that is inner-ring radial runout of 2.5 µm instead of 4 µm, and reference-face runout of 1.3 µm instead of 4 µm. So a 7009C-T-SUL-P4 is a valid dimensional interchange, but this bearing is tighter than P4 on runout.
An earlier description also gave the RHP number as …EP7. Both the carton and the ring engraving read EP3, so EP7 has been corrected. EP7 is kept as a cross-reference because it is the equivalent-envelope P4-grade version of the same bearing.

What these specs mean in practice

The 15° contact angle is the low-angle option in this range, the alternative being 25°. A shallower angle trades axial load capacity and axial stiffness for speed and lower heat generation, which is why 15° is the usual choice for high-speed spindles and 25° the usual choice where thrust dominates. The published figures for this size make the trade explicit: the 15° version is rated 24,400 N dynamic and runs to 30,500 rpm on oil/air, while the 25° equivalent is rated 23,100 N and 26,800 rpm — the 15° bearing is both faster and, in radial terms, slightly stronger, but it will carry less thrust before the contact ellipse starts to climb the raceway shoulder.

Light preload is a deliberate compromise too. Preload removes internal clearance so the balls cannot skid, which is what protects the raceways at speed, but every increment of preload costs speed. RHP’s published speed factors for a back-to-back pair are 0.85 for extra light, 0.80 for light, 0.60 for medium and 0.40 for heavy. Choosing light over medium therefore buys roughly a third more speed capability and gives up axial stiffness — 58 N/µm per light-preloaded pair against 85 N/µm medium.

The laminated phenolic resin cage is the reason this bearing runs quietly and fast, and it is also the reason it has a temperature ceiling. Phenolic is light, self-lubricating and outer-ring guided here, which suits high speed, but RHP’s maximum recommended operating temperature for phenolic-caged bearings is 120°C. Above that the cage, not the steel, is the limit.

Published ratings and mounting data

Bore 45 mm, outside diameter 75 mm, width 16 mm.
Contact angle 15°; single row; steel balls.
Basic dynamic load rating Cr 24,400 N.
Basic static load rating Cor 19,300 N.
Limiting speed, single bearing: 30,500 rpm oil/air, 18,800 rpm grease.
Axial preload, light, as a matched pair: 150 N. Axial stiffness, light, as a matched pair: 58 N/µm.
Effective load centre a = 16.0 mm.
Abutment dimensions: shaft shoulder d1 minimum 51 mm; housing shoulder D1 maximum 69 mm; D2 maximum 70 mm.
Chamfer limits r minimum 1.0 mm, r1 minimum 0.6 mm.
Internal free volume 11.2 cm³; pitch circle diameter for lubrication jets 55.6 mm.
Mass approximately 0.238 kg.
Ring and ball material: through-hardened carbon chrome bearing steel to BS970 534A99/535A99, equivalent to SAE 52100.
Maximum recommended operating temperature 120°C, set by the phenolic cage.

Quantity and configuration

This is one single bearing. The designation is the universal single form, not a duplex set, and one bearing is what is present and what is photographed. That distinction matters because angular contact bearings of this type cannot work alone — they take thrust in one direction only, so two opposed bearings, or a set of more than two, are always required in service. Universal face control is what makes a single unit useful: any two of these bearings taken from stock will produce the correct light preload when clamped together back-to-back or face-to-face, and will share load equally in tandem, with no custom-ground spacers needed. If you need a matched pair, order two.

Some of the cross-reference numbers carried on this listing, including the Timken/Fafnir 2MM9109WI CR DUL form, are duplex-pair designations. They are retained because they identify the same bearing envelope and buyers search them, but they describe how two bearings behave together and are not a claim about the quantity supplied here.

Fitting notes

Super-precision rings are thin and will take up the shape of whatever they are mounted in, transferring shaft and housing form errors straight into the raceway. Getting the seatings right is not optional on a bearing at this grade.

Recommended shaft fit for P3/P4 at this diameter is a mean interference of about 3T, with limits of +3/-2 µm, assuming a rotating inner ring and a load line constant in direction.
Recommended housing fit for a locating bearing at this diameter is a mean clearance of about 5C, limits +5/0 µm; for a sliding (non-locating) position, +7/+2 µm.
Abutment faces must be square to the shaft axis. Out-of-round and cylindricity errors on the shaft and housing should be held within ISO grade IT2 and IT3 respectively for P4, tightening to IT1 for P3 and P2 work.
The high point of radial runout is marked on the bearing: a small circle or burnished spot on the inner ring face, and a ‘V’ line on the outer ring outside diameter. Align these marks axially with each other and oppose them to the shaft or housing eccentricity to minimise assembled runout.
The ‘V’ line also indicates the direction of the contact angle, which is how you establish orientation before clamping.
Speed derating when paired or setted: back-to-back pair 0.80 of the single-bearing figure at light preload, a set of three 0.65, a set of four 0.60. Face-to-face mounting reduces the result by a further 50%. Spring-loaded tandem pairs use 0.95.
Lubrication: for oil/air, a guide delivery rate is V = 0.15 × d × B mm³/hour at normal speed. For grease, fill 30% of internal volume at low to medium speed, 20% at higher speed and 10–15% for very high speed spindles, then run the spindle up in staged increments and let temperature stabilise at each step. Overfilling with grease is the classic cause of abnormal heat generation.

Interchange guidance

In RHP’s current designation style this bearing is a 7009CTRSUL with a P3 precision grade — series 70, bore code 09, C for 15°, TR for the outer-ring-guided phenolic cage, SU for single universal, L for light preload. The widely searched 7009C-T-SUL-P4 and 7009CTSULP4 forms describe the same envelope, contact angle, cage and preload at the P4 grade, and the FAG/Schaeffler equivalent designation for the same envelope is B7009-C-T-P4S-UL. The Timken/Fafnir equivalent is the 2MM9109WI CR family, where 2MM denotes the 15° contact angle and CR the phenolic outer-land-riding cage.

When substituting across brands, verify three things rather than matching the base number alone: the contact angle letter, because the same-looking suffix means different angles in different schemes; the preload letter, because mixing a light-preload bearing with a medium-preload one in the same pair defeats the matching entirely; and the grade, because a P4 and a P3 bearing are dimensionally interchangeable but not equivalent in runout. RHP is now part of the NSK group, and RHP-branded super-precision product has been superseded by the corresponding NSK range, so RHP-marked stock of this designation is legacy inventory.