MRC7005Angular Contact Ball Bearing 25 x 47 x 12 mm, 29 Degree Contact Angle, Open, Aerospace Spec PWA 471547 D, 1 Pc

Product Description

What this part is

A single MRC angular contact ball bearing, 25 mm bore, 47 mm outside diameter, 12 mm width — the 7005 envelope. Open, 29° contact angle, and built to the Pratt & Whitney Aircraft specification PWA 471547 D, which is stamped against this part. New old stock American product for precision spindles, accessory drives, gearboxes and rotary positions carrying combined radial and one-direction thrust load.

Decoding the designation

7005 — the ISO 70-series angular contact size, 25 x 47 x 12 mm.
105KS — MRC’s legacy number for the same bearing, still widely used in older parts lists.
PWA 471547 D — Pratt & Whitney Aircraft specification number, meaning the bearing was produced against an aerospace procurement standard rather than a general industrial one.

Correcting the source data

MRC’s 7000-series angular contact bearings are built at a 29° contact angle. That is specific to MRC and it does not match the assumption most cross-reference tables make, which is that a bare 7005 designation means an ISO 40° bearing. Anyone specifying from the number alone will get the angle wrong, so it is stated plainly here: this bearing is 29°.

What these specs mean in practice

29° sits between the two familiar extremes and that is the whole point of it. A 15° bearing is the high-speed, low-heat choice with modest thrust capacity; a 40° bearing takes heavy thrust and is speed-limited by the heat a steep angle generates. At 29° the bearing carries appreciably more axial load than a 15° build and gives more axial stiffness, while still turning faster and cooler than a 40° one — which is precisely why MRC settled on it for aircraft accessory drives, where both duties matter and neither dominates. The practical consequence when substituting is that a 29° bearing will not match the deflection-under-thrust behaviour of either a 15° or a 40° bearing, so a preloaded pair built from mixed angles will not carry the load the designer intended.

Quantity and configuration

1 Pc — one bearing. The designation carries no SU, DU or DT suffix, so this was not supplied as part of a ground matched set.

Fitting notes

Angular contact bearings take thrust in one direction only, so something in the assembly must oppose it — a second bearing, a spring pack or a shoulder. Orientation matters: the wide land of the outer ring faces the thrust load, and a bearing fitted backwards puts the axial load onto a shoulder never designed for it. Interference fit adds internal preload, so check shaft and housing sizes against the drawing before pressing, and never press through the ball complement. Keep the bearing in its packaging until it goes on, and lubricate to whatever the assembly specifies rather than to habit — a part carrying an aerospace spec is usually in a position with a defined lubricant.

Interchange guidance

MRC was absorbed into SKF, so current-production equivalents come from the SKF catalogue. The critical point is the contact angle: because this MRC bearing is 29°, the nearest genuine equivalents are the 25° builds — SKF 7005 ACD/P4A, FAG B7005-E-T-P4S, NSK 7005A5 and Fafnir/Timken 3MM9105WI — and they are close but not identical on thrust behaviour. The 7005-C designation carried on this listing, along with SKF 7005 CD, FAG B7005-C-T-P4S and Fafnir 2MM9105WI, describes the 15° build of the same 25 x 47 x 12 mm envelope. Those are related sizes: same fit, different contact angle, so a different part rather than a substitute. If your application is genuinely angle-critical, confirm against the machine drawing or the PWA specification before ordering, and be aware that a bare 7005 from most other makers is a 40° bearing.