UCFL306 bearing: complete specifications & equivalents
The UCFL306 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 | 1400 g |
| Housing height H | 180 mm |
| Housing overall length L | 90 mm |
| Mounting bolt center distance J | 134 mm |
| Mounting hole diameter N | 23 mm |
| Manufacturer designation | UCFL306 |
| 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 & UCFL-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 UCFL-series | 12 mm |
| Largest outer diameter in UCFL-series | 300 mm |
| Width range across UCFL-series | 31–145 mm |
| Bore position in UCFL-series (smallest first) | 6 of 25 |
| Bore above smallest UCFL-series size | 18 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCFL306 | 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 UCFL306 model number is decoded
UCFL306 is an NTN two-bolt rhombus flanged unit — a setscrew-locking UC306D1 ball bearing insert pre-assembled in a FL306 cast-iron flange housing. Reading the designation: UC marks the wide-inner-ring, setscrew-locking insert; FL marks the two-bolt rhombus flange housing; the 3 code identifies the duty series and the final two digits encode the 30 mm bore. Key mounting figures: flange height H = 180 mm, overall length L = 90 mm across the diamond, bolt centres J = 134 mm, and each ear takes a 23 mm (M20) fastener for the 30 mm shaft. 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 diamond flange carries the shaft square to a vertical face — a welded frame, side plate or gearbox wall — so no base plinth and no shim pack under the bearing are required. The 25–50 mm bore band is the workhorse of industry — belt conveyors, fans, agricultural drives and small process machines — which is why this range has the fullest choice of series and cover options. On industrial centrifugal fans this size is standard at both shaft ends; fan loads are light but belt tension is not, and the cast housing dissipates the heat conducted out of the insert. Shim under the feet, never file the sole: full-area shim packs on both sides keep the bolt clamp load spread across the base, while a single thin shim pivots the housing and preloads the bearing. Basic ratings of the UC306D1 insert are 29.5 kN dynamic and 15 kN static; the assembled UCFL306 weighs about 1.4 kg.
Typical equipment & failure modes
Common applications
- belt conveyor head, tail and bend pulleys
- industrial fans and blowers
- agricultural augers and bucket elevators
- cold-store and winter-outdoor service needing low-temperature grease
Known failure patterns
- spherical-seat fretting that welds insert to housing and destroys the self-aligning action
- water-emulsified grease after washdown with the fitting facing upward
- setscrew loosening and inner-ring fretting on a shaft that was never re-torqued after run-in
Selection pitfalls — read before you substitute
- The 3-series insert makes UCFL306 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 rhombus flange, UCFL306 pulls against the frame through only two M20 bolts on 134 mm centres; the mounting plate must be stiff enough not to bend between them under belt load.
- When ordering covers for UCFL306, note the steel and cast-iron cover executions change the unit mass and envelope but not the 134 mm mounting centres.
- In this bore band the temptation is to choose UCFL306 on shaft size alone; belt pull often dominates the radial load, so rate the unit against the overhung pulley force, not just transmitted power.
Frequently asked questions
What are the dimensions of an UCFL306 mounted bearing?
UCFL306 takes a 30 mm shaft (insert UC306D1, 72 mm OD) and has a unit mass of about 1.4 kg. Flange figures: height H 180 mm, length L 90 mm, bolt centres J 134 mm, holes 23 mm for M20 bolts.
What does the UCFL306 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; FL the two-bolt rhombus flange housing; 3 is the duty series; the last digits encode the 30 mm bore. UCFL306 is built from housing FL306 plus insert UC306D1 (D1 = greasable).
How is UCFL306 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.
When should I choose a rhombus flange unit like UCFL306 instead of a pillow block?
Choose the UCFL306 two-bolt flange when the 30 mm shaft meets a vertical frame or side plate: the diamond housing bolts flush with two M20 bolts on 134 mm centres. A UCP pillow block is used when the shaft runs above a horizontal mounting surface.
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.