UCP324 bearing: complete specifications & equivalents
The UCP324 is a JIS B 1559 radial bearing sized 120 x 260 x 126 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 260 mm |
| Width B | 126 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 229 kN |
| Basic static load rating C0 | 185 kN |
| Fatigue load limit Pu | 10.5 kN |
| Mass | 50000 g |
| Housing height H | 160 mm |
| Housing overall length L | 570 mm |
| Mounting bolt center distance J | 450 mm |
| Mounting hole diameter N | 40 mm |
| Manufacturer designation | UCP324 |
| Standard | JIS B 1559 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & UCP-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 10.236 in |
| Width B | 4.961 in |
| ISO bore code | 24 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in UCP-series | 12 mm |
| Largest outer diameter in UCP-series | 300 mm |
| Width range across UCP-series | 31–145 mm |
| Bore position in UCP-series (smallest first) | 23 of 25 |
| Bore above smallest UCP-series size | 108 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP324 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range. Brand-specific OEM equivalents pending multi-source data. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the UCP324 model number is decoded
The NTN UCP324 unit pairs a UC324D1 sealed ball bearing insert with a one-piece P324 cast-iron pillow block housing, delivered aligned, greased and ready to bolt down. The UCP324 number follows NTN's mounted-unit convention: housing letter P, 3-series section, bore code for 120 mm; P324 and UC324D1 are the separate housing and insert part numbers inside. Shaft size is 120 mm; the cast base stands 160 mm to the shaft centre (H), is 570 mm long overall (L), and the two foundation holes on 450 mm centres (J) clear 40 mm M33 bolts. The 3-series section is the heavy-duty end of the range: a UC3 high-capacity insert in the longest, strongest housing, specified for shock loads and long conveyor centres. The upright base carries the shaft parallel to and above the mounting surface, which is the arrangement fan, conveyor and transmission drives use whenever a plinth or rail is available. Units in this bore class live in quarries, steel plants and port equipment: the ratings are high, but dust, water and foundation movement — not fatigue — usually decide the service life. Agricultural machinery — augers, stirrers, bucket elevators — uses this unit in the open, where the contact seals and slinger are the only barrier between the grease and chaff, dust and spray wash. The self-aligning capacity corrects only static misalignment of a few degrees; it does not forgive a bending shaft, which continuously pumps the outer ring and frets the spherical seat. Basic ratings of the UC324D1 insert are 229 kN dynamic and 185 kN static; the assembled UCP324 weighs about 50.0 kg.
Typical equipment & failure modes
Common applications
- primary crusher feeders
- steel-plant roller tables
- large induced-draft fans
- fan drives where belt tension, not transmitted torque, sets the radial load
Known failure patterns
- insert brinelling from hammer mounting or from belt tension applied to a stationary unit
- over-greasing that churns the charge, overheats the bearing and blows the seal lip
- cracked cast ear from mounting on an uneven face and pulling one bolt fully first
Selection pitfalls — read before you substitute
- Self-aligning is not the same as free to move: the UC324D1 insert of UCP324 pivots to correct static misalignment, but a continuously bending shaft still frets the spherical seat.
- XL units like UCP324 (120 mm bore, M33 bolts) are grouted, shimmed and aligned as civil works; bolting them straight to bare plate guarantees movement and foot cracking.
- The 3-series insert makes UCP324 the highest-rated unit at 120 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP324 needs a prepared horizontal surface at the 160 mm centre height: shim both feet with full-width packs so the 570 mm base seats over its full area.
- The D1 suffix on UC324D1 means the greasable execution; a unit without it has no fitting path, so do not assume every UCP324 on site accepts relubrication.
Frequently asked questions
When should I choose a pillow block like UCP324 instead of a flanged unit?
Choose the UCP324 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 160 mm above the 570 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
What loads can the UCP324 unit carry?
The UC324D1 insert is rated at 229 kN dynamic and 185 kN basic static (fatigue load limit 10.5 kN). Mounted units are predominantly selected on radial load from belt pull and overhung weight; axial capacity is limited and should be checked separately.
What are the dimensions of an UCP324 mounted bearing?
UCP324 takes a 120 mm shaft (insert UC324D1, 260 mm OD) and has a unit mass of about 50.0 kg. Housing figures: centre height H 160 mm, length L 570 mm, bolt centres J 450 mm, foot holes 40 mm for M33 bolts.
What does the UCP324 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; P the upright pillow block housing; 3 is the duty series; the last digits encode the 120 mm bore. UCP324 is built from housing P324 plus insert UC324D1 (D1 = greasable).
How is UCP324 locked to the shaft, and how tight should the setscrews be?
The UC324D1 insert uses two collar setscrews on the 120 mm shaft. Tighten them to NTN's torque table for this bore size in sequence — half torque on the first, full on the second, then back to the first — and re-torque after the first 24–48 running hours once the collar has seated.
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.