29388-EM bearing: complete specifications & equivalents
The 29388-EM is a ISO 104 radial bearing sized 440 x 680 x 145 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 440 mm |
| Outer diameter D | 680 mm |
| Width B | 145 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 5200 kN |
| Basic static load rating C0 | 19300 kN |
| Fatigue load limit Pu | 1560 kN |
| Reference speed (thermal) | 530 rpm |
| Limiting speed (mechanical) | 850 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 180000 g |
| Manufacturer designation | 29388 EM |
| Standard | ISO 104 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 13.1 spherical roller thrust bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 13.1 spherical roller thrust bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 13.1 spherical roller thrust bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 29300-series range
| Bore d | 17.323 in |
|---|---|
| Outer diameter D | 26.772 in |
| Width B | 5.709 in |
| ISO bore code | 88 |
| Radial section height (D−d)/2 | 120 mm |
| Smallest bore in 29300-series | 85 mm |
| Largest outer diameter in 29300-series | 1180 mm |
| Width range across 29300-series | 39–230 mm |
| Bore position in 29300-series (smallest first) | 25 of 31 |
| Bore above smallest 29300-series size | 355 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 29388-EM model number is decoded
Where a cylindrical roller thrust bearing would edge-load under deflection, 29388 EM aligns itself: 440×680×145 mm envelope, 19300 kN static rating, one load direction. The designation 29388 EM separates into 293 (series), 88 (440 mm bore) and EM; washers are separable for individual mounting. A minimum axial load of factor A 34 must be maintained — in the large 293 sizes this is a real force (often supplied by springs, oil pressure or the rotor weight), below it the rollers skid and smear. Selection arithmetic: C 5200 kN against C0 19300 kN gives a C0/C ratio of 3.71 — thrust bearings are chosen on static rating and F_a/C0 more often than on L10 life. Mounting: fit the shaft washer tight on the 440 mm seat, seat the sphered housing washer on its matching (often separately supplied) seating washer, and check the assembly swivels freely before applying the 5200 kN working load.
Typical equipment & failure modes
Common applications
- crane hook assemblies where the hook block turns under full load
- injection moulding machine and extruder screw thrust positions
- vertical hydro generators and large vertical pump motors
- coal mill, cement mill and sugar mill thrust bearings under shock load
Known failure patterns
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
- washer back-face fretting where the seat is too narrow to support the full ring face
- grease churning and overheating when a high-speed thrust position is over-packed
- rolling-contact fatigue spalling after the catalogue L10 life is exhausted
- cage wear from rollers being dragged through unloaded zones under fluctuating thrust
Selection pitfalls — read before you substitute
- Above 300 mm bore the minimum load is large (A 34 here): design the preload or lift sequence explicitly — an unloaded slow rotation glazes the 680 mm washer track.
- E, EM and EF suffixes are cage designs for different size bands, not quality grades: substitute only within the same envelope and check the lubricant compatibility of the cage material.
- The 5200/19300 kN figures assume the matching sphered seating washer is fitted where the catalogue calls for it; a flat housing seat removes the self-aligning function.
- Minimum load factor A 34 dominates commissioning: start the oil flow and preload before rotation, especially on 293 bearings where an unloaded cold start smears the rollers.
- The spherical seat tolerates static misalignment, not a continuously rocking housing — a loose sphered seat frets under oscillation and needs the catalogue seat tolerances plus clean, greased contact.
- The 5200/19300 kN ratings and 180000 g mass are SKF catalogue values transcribed from ch. 13.1 of PUB BU/P1 17000 (PDF table page 928); mounting data — the minimum axial load factor A — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
Can the 29388 EM also carry radial load?
Yes, up to roughly 55 % of the simultaneous axial force, thanks to the steep contact angle of the barrel rollers. Beyond that mix, specify a separate radial bearing; the primary duty remains one-direction thrust.
How is a 29388 EM mounted?
Tight shaft washer on the 440 mm seat, sphered housing washer on its matching seating washer, induction heating for large sizes, oil at the catalogue level before start, and the factor-A 34 preload verified at commissioning.
What are the dimensions and ratings of the 29388 EM?
A 29388 EM measures 440 mm bore × 680 mm outside diameter × 145 mm width (17.323 × 26.772 × 5.709 in). From SKF catalogue PUB BU/P1 17000: dynamic C 5200 kN, static C0 19300 kN, fatigue limit Pu 1560 kN, reference speed 530 r/min, limiting speed 850 r/min, mass about 180000 g. Minimum axial load factor A 34 must be maintained in service.
How is the 29388 EM designation read?
293 is the dimension series (medium 293 series) and 88 the 440 mm bore (code 88 × 5); EM is the cage execution (machined brass EM cage). The sphered housing washer provides self-alignment.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 13.1 spherical roller thrust bearings on 2026-09-27. Read our editorial & correction policy.