UCP306 bearing: complete specifications & equivalents
The UCP306 is a JIS B 1559 radial bearing sized 30 x 72 x 43 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 | 30 mm |
| Outer diameter D | 72 mm |
| Width B | 43 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 29.5 kN |
| Basic static load rating C0 | 15 kN |
| Fatigue load limit Pu | 1.14 kN |
| Mass | 1800 g |
| Housing height H | 50 mm |
| Housing overall length L | 180 mm |
| Mounting bolt center distance J | 140 mm |
| Mounting hole diameter N | 17 mm |
| Manufacturer designation | UCP306 |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 1.693 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 21 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) | 6 of 25 |
| Bore above smallest UCP-series size | 18 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP306 | 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 UCP306 model number is decoded
The NTN UCP306 unit pairs a UC306D1 sealed ball bearing insert with a one-piece P306 cast-iron pillow block housing, delivered aligned, greased and ready to bolt down. The UCP306 number follows NTN's mounted-unit convention: housing letter P, 3-series section, bore code for 30 mm; P306 and UC306D1 are the separate housing and insert part numbers inside. Shaft size is 30 mm; the cast base stands 50 mm to the shaft centre (H), is 180 mm long overall (L), and the two foundation holes on 140 mm centres (J) clear 17 mm M14 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. This mid bore range dominates agricultural and bulk-handling builds, where standard shafts, cast feet and greasable inserts keep replacement a stock-room, not a workshop, exercise. 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 UC306D1 insert are 29.5 kN dynamic and 15 kN static; the assembled UCP306 weighs about 1.8 kg.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- agricultural augers and bucket elevators
- small crushers and screening feeds
- wet, abrasive or chemically aggressive environments relying on the lip seals and slingers
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
- When ordering covers for UCP306, note the steel and cast-iron cover executions change the unit mass and envelope but not the 140 mm mounting centres.
- The standard section of UCP306 can look adequate at 30 mm while the X or 3 section is the real choice for long conveyor centres; compare ratings rather than fitting the same unit line-wide.
- The 3-series insert makes UCP306 the highest-rated unit at 30 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP306 needs a prepared horizontal surface at the 50 mm centre height: shim both feet with full-width packs so the 180 mm base seats over its full area.
- Do not confuse UCP306 with a bare UC306D1 bearing: replacing only the insert is possible, but the housing P306 must be unworn and the spherical seat cleaned and coated with anti-seize.
Frequently asked questions
When should I choose a pillow block like UCP306 instead of a flanged unit?
Choose the UCP306 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 50 mm above the 180 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 UCP306 unit carry?
The UC306D1 insert is rated at 29.5 kN dynamic and 15 kN basic static (fatigue load limit 1.14 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 UCP306 mounted bearing?
UCP306 takes a 30 mm shaft (insert UC306D1, 72 mm OD) and has a unit mass of about 1.8 kg. Housing figures: centre height H 50 mm, length L 180 mm, bolt centres J 140 mm, foot holes 17 mm for M14 bolts.
What does the UCP306 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 30 mm bore. UCP306 is built from housing P306 plus insert UC306D1 (D1 = greasable).
How is UCP306 locked to the shaft, and how tight should the setscrews be?
The UC306D1 insert uses two collar setscrews on the 30 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.