FAGL15TA708YPThin Section Angular Contact Ball Bearing, 7.500 x 8.500 x 1/2 in, Square 1/2 x 1/2 in Section, Type A Single Row, Open, Brass Separator

Product Description

What this part is

A thin section angular contact ball bearing, 7.500 in bore x 8.500 in outside diameter x 0.500 in wide. It is the direct equivalent of Kaydon KD075AR0 and Silverthin SD075AR0 — open, single row, Type A angular contact, with 1/4 in balls in a one-piece machined brass pocket separator, ABEC Class 1.

The square cross section, proved from the numbers

Outside diameter minus bore is 8.500 − 7.500 = 1.000 in, giving 0.500 in of wall each side. That equals the 1/2 in race width exactly, so the cross section is a true 1/2 x 1/2 in square — the defining geometry of a thin section bearing. This arithmetic confirms the title dimensions without needing a datasheet, and it is worth knowing as a general test: in this product class, if the wall per side equals the width, the dimensions are internally consistent.

Decoding the designation — corrected

L15 — FAG thin section series prefixT — the cross-section code. In this family Q, R, S and T are ascending section sizes mapping to the Kaydon letters: Q = 1/4 x 1/4, R = 5/16 x 5/16, S = 3/8 x 3/8, T = 1/2 x 1/2. So the T here is what makes this the 1/2 in sectionA — Type A, single row angular contact, thrust in one direction708 — the bore in whole inches plus sixteenths, not hundredths. 708 reads as 7 and 08/16, which is 7.500 in. This is corroborated independently by SKF, which uses the identical digits in its FPAD708 equivalentYP — one-piece machined brass circular-pocket separator

Being straight about provenance: no published Schaeffler or FAG document giving the Q/R/S/T section table could be located, so the decode above is derived from three independently verified dimensional data points plus the Silverthin interchange rather than from a FAG datasheet. The dimensions themselves are firmly published; the letter-to-section mapping is a well-supported deduction.

Published ratings and mounting data

Static radial load capacity: 6,320 lbfDynamic radial load capacity: 2,536 lbf (Kaydon method); 4,608 lbf on the ISO 281:1990 basis, shown for comparison only — the two are not interchangeable figuresStatic thrust load capacity: 18,240 lbfDynamic thrust load capacity: 6,250 lbfLand diameters: L1 7.870 in, L2 8.130 in, L3 (counterbore) 8.236 inBall diameter: 1/4 inMaximum fillet radius cleared: 0.060 inRace width tolerance: +0.000 / −0.005 inPrecision: ABEC Class 1Weight: 1.42 lbCorners: normally chamfered

Radial and thrust ratings are not additive. A bearing carrying both at once must be checked against a combined-load calculation; comparing your resultant against either column alone will overstate what the bearing can do.

Ball count and contact angle are not published and are deliberately omitted. On contact angle this is not a gap in our research but a property of the product: Kaydon states that a Type A bearing “requires the application of thrust to establish contact angle,” so the angle is preload-dependent rather than a fixed catalogue value. Any source quoting a specific degree figure for a Type A thin section is quoting something the manufacturer does not publish.

What these specs mean in practice

A thin section bearing trades load capacity for envelope and mass. You accept a much lower rating than a conventional ball bearing of the same outside diameter in exchange for a very thin radial wall and a very large open bore. The design driver is almost always something that has to pass through the middle: a hollow shaft, a cable bundle, a slip ring, a laser path, a coolant line. Hence their dominance in robotics joints, gimbals, rotary and index tables, medical imaging gantries, semiconductor wafer handlers, and optical and radar positioners.

Fitting notes

Because the rings are thin they are flexible, and a thin section bearing will faithfully adopt the out-of-roundness of whatever you clamp it into. That is by far the most common cause of premature failure in this product class. Housing bores and shaft seats must be machined round and flat to a tighter standard than a conventional bearing would tolerate, the surrounding structure must be rigid, and clamping load must be applied uniformly around the circumference rather than through a few bolts. Respect the 0.060 in maximum fillet radius at both shoulders.

Type A carries thrust in one direction only. If your application reverses thrust a single Type A will unload on the reverse stroke, and you need a duplex pair (BR0 back-to-back or FR0 face-to-face) or a four-point contact bearing (XP0) instead. Being open, it also ships with no lubricant retention at all — grease selection, retention and sealing are the surrounding design’s responsibility.

Interchange guidance

Direct equivalents: Kaydon KD075AR0, Silverthin SD075AR0, SKF FPAD708, NSK NBA19012, NTN KYD075, RBC KD075AR0, SSB RD075AR0, INA CSAD075. FAG and INA are both Schaeffler Group brands, so the INA reference is an in-house sibling rather than a third-party substitute.

Related but functionally different, and not substitutes: SD075CP0 / KD075CP0 (radial contact), SD075XP0 / KD075XP0 (four-point contact), SD075BR0 / KD075BR0 (duplex back-to-back), SD075FR0 / KD075FR0 (duplex face-to-face). No sealed variant is catalogued at this bore and section.

Central Surplus also stocks FAG L15QA408YP (4.500 x 5.000 x 1/4 in), L15RA700YP and L15RA400YP from this same family.