NSK7008CTYDBC2P5Super Precision Angular Contact Ball Bearing Matched Set 40x68x15 mm, 15 Degree Contact Angle, ABEC 5, Back-to-Back Duplex, Polyamide Cage

Product Description

What this part is

A matched pair of super precision angular contact ball bearings in the ISO 70 light series, 40 mm bore, 68 mm outside diameter, 15 mm width per bearing, ground for back-to-back duplex mounting.

Decoding the designation

7008 — ISO 70 series angular contact ball bearing, 40 x 68 x 15 mm.
C — NSK contact angle code for 15°. NSK uses A for 30° and A5 for 25°, so this is the high speed, lower thrust member of the family.
TY — NSK polyamide cage code.
DB — duplex mounted back-to-back.
P5 — ABEC 5 tolerance class.
C2 — carried on the carton but not decoded. See the note below.

Correcting the source data

The previous listing text was eBay boilerplate with no specification content at all and has been replaced. Two points in the number need stating honestly rather than smoothed over. First, C2 is normally a radial internal clearance class, and a clearance class sits oddly on a duplex set whose whole purpose is to run in preload rather than clearance — so C2 is retained as a carton marking and search term and is explicitly recorded as undecoded, not translated into a preload claim. Second, this set is P5 (ABEC 5), not the P4 that most 7008 duplex sets carry; the lower class is a real difference in running accuracy and is stated plainly rather than upgraded.

What these specs mean in practice

15° buys speed and loses thrust. On a 40 mm bore spindle that trade is usually the right one, because the limiting factor is heat rather than axial capacity. Back-to-back mounting spreads the two contact lines outward, giving the set real moment stiffness — it resists the spindle nose trying to tilt under a side cutting load, which a tandem pair cannot do. ABEC 5 is a step down from ABEC 7 in bore, outer diameter and runout tolerance; it is entirely adequate for grinding spindle support and precision gearbox positions, and it is not adequate where a published sub micron runout figure is a contract requirement.

Quantity and configuration

The bearings are supplied as a matched back-to-back pair and must stay together. Stock is held in a way that does not distinguish pairs from individual pieces, so no total piece count is claimed on this page — confirm the quantity you need with us before ordering multiples.

Fitting notes

Align the ring etching as marked and clamp both rings fully. A duplex set that is not clamped solidly on both the inner and the outer ring never closes its ground offset, and then it runs with play instead of preload — the failure looks like a bearing defect but is a mounting error. Keep the polyamide cage below roughly 120 °C continuous.

Published ratings and mounting data

Load ratings and limiting speed are not published by NSK for this exact set designation in any source we could verify, and set ratings are not double the single bearing figures, so those cells are left blank rather than filled with a sibling designation’s numbers.

Interchange guidance

Same envelope 15° super precision alternatives are found as B7008C-T-P4S (FAG), 7008CD/P4A (SKF) and 2MM9108WI (Fafnir/Timken) — note those are P4 class parts, so they are an upgrade rather than a like for like swap against this P5 set. Confirm preload and arrangement before substituting.