SNFASuper Precision Angular Contact Ball Bearing SINGLE Half-Pair, 40 x 80 x 18 mm, 15 Degree Contact Angle, ABEC 7, Phenolic Cage, Universally Ground

Product Description

What this part is

A single super precision angular contact ball bearing from the SNFA E-series metric spindle-bearing range, 40 mm bore, 80 mm outside diameter, 18 mm width, single row, 15° contact angle, ABEC 7 precision class, with a machined phenolic cage. The ring faces are universally ground, so the bearing can be paired with another of the same designation in any of the three standard arrangements.

This is ONE bearing, not a pair

The suffix -1/2PR means one half of a pair. It is a unit-of-sale marking, not a design feature: the part is a single bearing that belongs to a universally-ground pairing family, sold individually. A buyer who expects a matched pair and receives one bearing has a dispute, so it is stated plainly here, in the title, and in the Unit Quantity attribute. The SNFA carton holds one bearing. If you need a duplex pair for a spindle nose, take two units of this listing; if you need a full triplex set, take three.

Decoding the designation

E240 – SNFA’s metric spindle-bearing series numbering; the 240 size code corresponds to the 40 mm bore, 80 x 18 mm envelope, matching the ISO 7208 boundary dimensions.

7CE1 – the 7-series 15° contact-angle spindle bearing design.

DU – duplex universal: ring faces relieved so any two bearings of this designation will mount back-to-back, face-to-face or in tandem and arrive at the intended preload.

-1/2PR – half of a pair, i.e. one bearing.

DUL, seen on the cross-reference form 7208-C-DUL, denotes duplex universal light preload; DUM would be medium and DUH heavy.

Reading the carton alongside the catalogue

The blue SNFA carton is labelled E-240-CE1D / SNFA, and the outer ring is marked SNFA, E 240 and ITALY. The seller designation E240-7CE1DU-1/2PR is the fuller catalogue form of the same bearing including the pairing and unit-of-sale suffixes; the abbreviated carton form omits them. Both are listed so either search finds the part.

What these specs mean in practice

The 15° contact angle is the high-speed choice. A shallower angle keeps more of the load line radial, which reduces the centrifugal and gyroscopic burden on the ball set, so the bearing turns faster and runs cooler than a 25° equivalent of the same size. The trade-off is axial stiffness: under heavy thrust, a 25° bearing holds spindle position better. For a 40 mm high-speed grinding or milling spindle, 15° is normally correct.

The cage is a red-brown machined phenolic laminate. Phenolic is the traditional spindle cage material because it is light, self-lubricating, quiet and forgiving of marginal lubrication. Its limits are thermal and chemical: it softens and can delaminate above roughly 120 °C and is not compatible with every synthetic lubricant, so it belongs in an oil-mist, oil-air or grease-for-life spindle rather than a hot, heavily loaded position.

Universally ground rings put the arrangement decision in the fitter’s hands rather than the part number. Back-to-back gives the widest load-line spread and the greatest moment stiffness, which is what a spindle nose wants. Face-to-face tolerates a little shaft-to-housing misalignment. Tandem doubles axial capacity in one direction only.

Mounting data

Boundary dimensions are ISO-standardised: 40 mm bore, 80 mm outside diameter, 18 mm width. Contact angle 15° nominal. Precision class P4 / ABEC 7. Machined phenolic land-riding cage, open, oil lubricated. Duplex universal grind, supplied as one half of a pair.

Interchange guidance

Equivalent designation forms include E240-7CE1DU-1/2PR, E240 7CE1 DU 1/2PR, E-240-7CE1-DU, E-240-CE1D, E2407CE1DU and E240 7CE1. The ISO base number is 7208 and the paired form is written 7208-C-DUL or 7208CDUL. The obsolescence trail is SNFA to Schaeffler (FAG), and the Schaeffler successor family is B7208-C-T-P4S. Same-envelope equivalents include NSK 7208CTYDULP4, NTN 7208CGD2GLP4 and Timken/Fafnir 2MM208WI DUL, but preload grade and cage material vary between brands, so match the full suffix rather than the base number alone.