UCP312 bearing: complete specifications & equivalents
The UCP312 is a JIS B 1559 radial bearing sized 60 x 130 x 71 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 | 60 mm |
| Outer diameter D | 130 mm |
| Width B | 71 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 90.5 kN |
| Basic static load rating C0 | 52 kN |
| Fatigue load limit Pu | 4.1 kN |
| Mass | 9400 g |
| Housing height H | 85 mm |
| Housing overall length L | 330 mm |
| Mounting bolt center distance J | 250 mm |
| Mounting hole diameter N | 25 mm |
| Manufacturer designation | UCP312 |
| 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 | 2.362 in |
|---|---|
| Outer diameter D | 5.118 in |
| Width B | 2.795 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 35 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) | 12 of 25 |
| Bore above smallest UCP-series size | 48 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP312 | 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 UCP312 model number is decoded
UCP312 belongs to NTN's UCP line of cast-iron pillow blocks built to JIS B 1559 housing boundary dimensions around a JIS B 1558 UC312D1 insert. The code breaks down as insert family UC, housing form P (pillow block), duty series 3, bore code ending in the 60 mm shaft size; the unit is built from insert UC312D1 and housing P312. For layout work on UCP312: the 60 mm shaft centre sits 85 mm above the sole (H), the footprint is 330 mm long (L), bolt centres are 250 mm (J), and the foot holes suit M20 (25 mm) 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. Large-bore mounted units like this are selected on calculated bearing life plus foundation quality — the cast base is now a structural part of the drive, not just a convenient clamp. Cement plant clinker conveyors fit this size under insulation and heat shields; radiant heat dictates both the grease grade and a relubrication interval far shorter than the load alone would suggest. If the unit is the locating bearing, clamp the inner ring with both setscrews and keep the housing feet tight; the opposite unit on the shaft must be the float design with slots, or thermal growth preloads both bearings. Basic ratings of the UC312D1 insert are 90.5 kN dynamic and 52 kN static; the assembled UCP312 weighs about 9.4 kg.
Typical equipment & failure modes
Common applications
- cement and clinker handling
- sugar-mill and fertiliser plant drives
- heavy bulk-handling conveyors
- frequent stop-start and reversing duty such as shuttle and tripper conveyors
Known failure patterns
- setscrew loosening and inner-ring fretting on a shaft that was never re-torqued after run-in
- 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
Selection pitfalls — read before you substitute
- The 3-series insert makes UCP312 the highest-rated unit at 60 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP312 needs a prepared horizontal surface at the 85 mm centre height: shim both feet with full-width packs so the 330 mm base seats over its full area.
- When ordering covers for UCP312, note the steel and cast-iron cover executions change the unit mass and envelope but not the 250 mm mounting centres.
- UCP312 at 60 mm uses M20 bolts that need a torque wrench and a cross pattern; pulling one bolt first tips the 85 mm centre height and binds the insert.
Frequently asked questions
What are the dimensions of an UCP312 mounted bearing?
UCP312 takes a 60 mm shaft (insert UC312D1, 130 mm OD) and has a unit mass of about 9.4 kg. Housing figures: centre height H 85 mm, length L 330 mm, bolt centres J 250 mm, foot holes 25 mm for M20 bolts.
What does the UCP312 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 60 mm bore. UCP312 is built from housing P312 plus insert UC312D1 (D1 = greasable).
How is UCP312 locked to the shaft, and how tight should the setscrews be?
The UC312D1 insert uses two collar setscrews on the 60 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.
When should I choose a pillow block like UCP312 instead of a flanged unit?
Choose the UCP312 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 85 mm above the 330 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
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.