RHP7013SCTDULP3Hybrid Ceramic Super Precision Angular Contact Ball Bearing 65x100x18 mm, Silicon Nitride Balls, 15° Contact Angle, P3 Accuracy, Machined Phenolic Cage, Universal Duplex Light Preload — Complete Matched Pair

Product Description

What this part is

Two single-row hybrid ceramic super-precision angular contact ball bearings — together one complete matched duplex pair — 65 mm bore × 100 mm outside diameter × 18 mm width. Steel rings, ceramic balls, a machined laminated phenolic cage, a 15° contact angle, light preload set at manufacture, and RHP’s intermediate P3 accuracy grade. This is a high-frequency spindle bearing: the sort of part fitted to grinding spindles, high-speed milling heads and motorised spindles where the limiting factor is heat and centrifugal ball load rather than static capacity.

Decoding the designation

The cartons and both bearing rings read 7013SCTDULP3. This uses the older RHP format in which the construction code sits ahead of the contact angle, which is why the S comes where it does:

7013 – single-row angular contact ball bearing, ISO dimension series 10, bore code 13 = 65 mm bore. Boundary dimensions 65 × 100 × 18 mm.
S – construction code for ceramic ball type. RHP’s published construction options for this family are the unmarked normal (steel ball) type, R for reverse type, and S for ceramic ball. So this is a hybrid bearing: steel rings running silicon nitride balls. The source record’s “hybrid ceramic” claim is correct, and the S is where that comes from.
C – 15° contact angle in RHP’s scheme. RHP publishes C = 15° and E = 25°; NSK’s letter for the same 25° bearing is A5 and SKF’s is ACD, so it matters which brand’s key you are reading. This one is RHP’s, and it is 15°.
T – machined laminated phenolic resin cage. Visible in the photographs as the dark reddish-brown ring between the raceways, which is the reliable field indicator for phenolic.
DU – duplex universal. A matched pair whose faces are ground so it can be mounted back-to-back, face-to-face or in tandem with no spacers and no change to the set preload.
L – light preload, which RHP describes as the class most frequently selected. The others are EL, M and H.
P3 – and this one deserves its own section below, because it is not an ABEC grade.

P3 is not an ABEC grade — read this before you cross-reference:
RHP’s precision table maps P4 to BS292 EP7, ABEC 7 and ISO 492 Class 4, and P2 to EP9, ABEC 9 and ISO Class 2. P3 is deliberately left with a dash in the ABEC column. It is an RHP-specific intermediate grade defined as P4 external tolerances combined with P2 running accuracy — in other words, the bore and outside-diameter tolerances of a Class 4 bearing with the runout of a Class 2 one. Anyone who tells you P3 equals ABEC 7 is understating the running accuracy; anyone who calls it ABEC 9 is overstating the dimensional tolerance. The practical consequence is useful: P3 fits shafts and housings machined for a Class 4 bearing while running as true as a Class 2, which is exactly what you want when you are retrofitting accuracy into an existing spindle rather than building a new one.

What the ceramic balls actually buy you

Silicon nitride balls weigh roughly 40 % of a steel ball of the same diameter, and that single fact drives everything else. Lower ball mass means lower centrifugal load at speed, which means the contact angle stays closer to its design value as the spindle winds up, which means less contact stress, less heat and higher usable speed. The balls are harder than the rings and have a lower coefficient of friction against steel, so a hybrid bearing runs cooler on the same lubricant and survives marginal lubrication better. Ceramic is also electrically insulating, which is why hybrid bearings are the standard answer to shaft-current damage on motorised and inverter-driven spindles.

The trade is capacity and cost. Silicon nitride has a higher elastic modulus than steel, so the contact patch is smaller and the published dynamic load rating of a hybrid bearing is materially lower than the steel-ball version of the same envelope — not a defect, just a different design point. A hybrid pair is the right choice when speed, heat and electrical isolation are the constraint; a steel pair is the right choice when static and dynamic load are.

Why we are not publishing a load rating

RHP’s super-precision catalogue tabulates load ratings and limiting speeds for the steel-ball bearings only. It lists the ceramic-ball construction as an option in the designation key but publishes no separate rating table for it, and we have not found one from NSK either. We are therefore leaving the dynamic and static load ratings and the limiting speed blank for this part rather than borrowing the steel figures, which would overstate capacity by a wide margin. For scale: RHP rates the steel-ball 7013 at 15° at Cr 37,000 N, while SKF’s hybrid ceramic bearing in the same 65 × 100 × 18 mm envelope is published at roughly 19.5 kN. The gap is the point. If you need a certified rating for this exact designation, NSK UK at Newark holds the original RHP data.

Published geometry and mounting data

Boundary and abutment dimensions are set by the ISO envelope and are the same for either ball material. From the RHP super-precision catalogue, 70xx ISO series 10 table, 7013:

Bore d – 65 mm
Outside diameter D – 100 mm
Width B – 18 mm
Chamfer r min / r1 min – 1.1 mm / 0.6 mm
Shaft abutment diameter d1 min – 72 mm
Housing abutment diameters D1 max / D2 max – 93 mm / 95 mm
Effective load centre a – 20.0 mm (15°)
Internal free volume – 19.0 cm³
Lubrication jet pitch circle dT – 77.5 mm
Mass – 0.435 kg per bearing for the steel-ball variant; the ceramic-ball version is lighter and RHP publishes no separate figure
Axial preload, light class, 15°, bore code 13 – 250 N per pair for the steel-ball variant (RHP’s other classes: EL 125 N, M 540 N, H 1,080 N)
Axial stiffness, light class, 15° – 82 N/µm for the steel-ball variant; ceramic balls raise contact stiffness, so treat this as indicative only

Quantity and configuration

This listing supplies two bearings — one complete matched duplex pair, and the photographs show it plainly: two individually sealed RHP bags each containing one bearing, alongside two original RHP cartons both labelled 7013SCTDULP3. Nothing has been split and nothing is missing. This matters because DUL describes how two bearings behave together, and duplex sets are routinely broken up in surplus — a DUL carton with one bearing in it is a single, not a pair. Here the pair is intact.

Keep the two together and keep the marked faces oriented as RHP ground them. Universal facing lets you choose the arrangement; it does not let you mix halves between sets, because the preload was established across these two specific bearings.

Fitting notes

Universal facing removes the usual duplex work: no measuring face steps, no custom spacers, the same catalogue preload back-to-back or face-to-face, and equal load sharing in tandem. Respect the abutment diameters above so shaft shoulder and housing land clear the corner radii — at P3 running accuracy a shoulder fouling a chamfer will distort the ring and waste the accuracy you paid for. Do not press through the cage. If the spindle is inverter driven, note that the ceramic balls give electrical isolation across the bearing, so check that any shaft grounding ring or brush in the machine is still appropriate for the new arrangement.

Interchange guidance

The SKF number carried in this listing, 7013 CD/HCP4A DBA, is a close same-envelope equivalent and worth reading carefully: CD is SKF’s 15° high-capacity design, HC is SKF’s suffix for hybrid ceramic (steel rings, silicon-nitride balls), P4A is SKF’s own class-4-dimensional-with-better-than-class-4-runout grade, and DBA is a matched back-to-back pair at light preload. So contact angle, ball material and preload all match this RHP pair. Two differences to note: SKF’s DBA is a fixed back-to-back pair whereas RHP’s DUL is universally faced and will also mount face-to-face or tandem, and SKF’s P4A is not the same definition as RHP’s P3. The modern NSK reading of the RHP designation is 7013C TR DUL P3 in the ceramic-ball construction. RHP itself became part of NSK when NSK acquired the RHP group in the early 1990s; the business traded as NSK-RHP until the name reverted to plain NSK in November 2000, and these bearings are still made at the former Ransome & Marles works in Newark, England. Other same-envelope hybrid options are FAG HCB7013-C-T-P4S and NTN 7013 HX series. Confirm ball material, contact angle, preload class and accuracy grade against your spindle drawing before substituting.

Markings we have not decoded

Alongside the part number the cartons carry RR, the legend NB5U5, the notations D:T and d:T, MADE IN ENGLAND, and a partly legible code that reads as 6G-08. The rings are additionally engraved RHP ENGLAND and 2C. None of these appears in any RHP or NSK designation key we can source, so we are reproducing them as printed rather than interpreting them. One observation offered as an observation only: RHP’s catalogue uses Klüber Isoflex NBU15 as its reference grease, and NB5U5 may be that name on a worn label, which would indicate a factory grease fill — but the characters do not match and we are not asserting it. If your specification depends on the lubricant, treat these bearings as unknown fill and ask.