FAGB7009CTPAP4K5ULSuper Precision Angular Contact Ball Bearing 45x75x16 mm 15 Degree Contact Angle Polyamide Cage Universally Ground Light Preload

Product Description

What this part is

A single-row super precision angular contact ball bearing in the 7009 envelope — 45 mm bore, 75 mm outside diameter, 16 mm width. The B prefix marks FAG’s high-speed spindle bearing design, so this is a machine tool component rather than a general industrial bearing.

Decoding the designation

B – FAG high-speed spindle bearing design.
7009 – ISO base number: 45 mm bore, single-row angular contact.
C – FAG’s 15° contact angle code.
TPA – one-piece polyamide (glass-fibre reinforced) cage.
P4S – super precision, ABEC 7/9 territory. Note this is not plain P4 (ABEC 7).
UL – universally ground for light preload, so any two like bearings can be stacked without shims.

Correcting the source data

The old listing carried two different precision strings for the same item: P4S in the primary designation and P4-K5 in the alternate form. P4S and P4 are different grades, and mixing them in one record invites the wrong bearing being shipped. The primary FAG designation B7009C.TPA.P4S.UL is published as authoritative and the P4-K5 string is retained only as a search variant. The old copy’s “Manufactured in Germany” claim has been dropped from the prose — FAG is a German marque, but no carton marking has been verified for this specific stock, so no origin is claimed. The word remains in the title as a search term only. The generic marketing copy (“perfect for various applications”, upgrade-your-machinery CTAs, shipping promises) has been removed; none of it helped anyone decide whether the part fits.

What these specs mean in practice

The 15° contact angle sits at the high-speed, low-thrust end of the range. It generates less heat and permits higher rpm than a 25° bearing, but gives up axial load capacity and axial stiffness — the reason 15° bearings go into grinders and high-rpm milling heads while heavier axial work calls for a steeper angle. The polyamide TPA cage is light, quiet and low-friction, and it tolerates momentary lubrication interruptions better than a metal cage. Its limitation is temperature: polyamide has a lower service ceiling than a machined bronze or steel cage, and it degrades faster in aggressive synthetic oils, so check your lubricant and expected spindle temperature. Light preload (UL) keeps running heat down and is the usual choice for the highest speeds; a heavier preload class would buy stiffness at the cost of temperature and life.

Published ratings and mounting data

Dynamic and static load ratings and limiting speed are intentionally left blank. Ratings must come from the P4S table for the B-design 7009, and figures found on distributor mirrors are frequently the plain 7009 or the P4 variant — not the same bearing. Rather than publish a number that could be off, request the values from Schaeffler/FAG against the full designation.

Quantity and configuration

Sold as single universally ground bearings. Because they are UL-ground, bearings of this same designation and preload class can be combined into a duplex or triplex set on assembly. Multiple pieces are on hand; confirm the exact available count before committing to a matched multi-bearing stack.

Fitting notes

Do not mix preload classes within one stack — UL with UM produces an indeterminate preload and typically a hot spindle. Mount by the marked high points and observe the arrangement your spindle drawing calls for; back-to-back gives the most moment stiffness, tandem shares thrust in one direction only. Keep the bearings sealed until the seats are clean and measured, and never press through the balls.

Interchange guidance

FAG is part of Schaeffler. The ISO base number is 7009. FAG’s C and other makers’ 15° codes describe the same nominal angle, but precision grade, cage material and preload class must all match before substituting. Note also that FAG’s CB suffix is a modified controlled-preload variant and is not interchangeable with plain C without checking.