UCFL307 bearing: complete specifications & equivalents
The UCFL307 is a JIS B 1559 radial bearing sized 35 x 80 x 48 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 | 35 mm |
| Outer diameter D | 80 mm |
| Width B | 48 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 37 kN |
| Basic static load rating C0 | 19.1 kN |
| Fatigue load limit Pu | 1.47 kN |
| Mass | 1700 g |
| Housing height H | 185 mm |
| Housing overall length L | 100 mm |
| Mounting bolt center distance J | 141 mm |
| Mounting hole diameter N | 23 mm |
| Manufacturer designation | UCFL307 |
| 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 | 1.378 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 1.89 in |
| ISO bore code | 07 |
| Radial section height (D−d)/2 | 22.5 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) | 7 of 25 |
| Bore above smallest UCFL-series size | 23 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCFL307 | 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 UCFL307 model number is decoded
The NTN UCFL307 flanged unit combines a sealed UC307D1 insert with a diamond-shaped FL307 cast-iron housing that bolts flat against a machine frame. The code breaks down as insert family UC, housing form FL (flange), duty series 3, bore code ending in the 35 mm shaft size; the unit is built from insert UC307D1 and housing FL307. For the frame-face drawing of UCFL307: the two holes are 141 mm apart (J), the rhombus spans 100 mm (L) and 185 mm (H), and M20 (23 mm) bolts clamp it around the 35 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. 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. Bottle, can and carton conveyor lines run dozens of these units per line, so the decision is driven by interchange stock and the time to swap a failed unit during a change window. Never mount by striking the insert or its inner ring: press or drive on the housing only. Impact through the rolling elements transmits straight to the seals and leaves brinell marks that announce themselves as noise weeks later. Basic ratings of the UC307D1 insert are 37 kN dynamic and 19.1 kN static; the assembled UCFL307 weighs about 1.7 kg.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- agricultural augers and bucket elevators
- small crushers and screening feeds
- continuous one-direction running where creep risk concentrates on the setscrew points
Known failure patterns
- grease starvation on long intervals in hot positions, with the ball set running on dried thickener
- fretting corrosion of the shaft journal under the wide inner ring after years of micro-creep
- lip-seal failure from grit past the slinger, followed by grease loss and abrasive wear
Selection pitfalls — read before you substitute
- The 3-series insert makes UCFL307 the highest-rated unit at 35 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a rhombus flange, UCFL307 pulls against the frame through only two M20 bolts on 141 mm centres; the mounting plate must be stiff enough not to bend between them under belt load.
- The D1 suffix on UC307D1 means the greasable execution; a unit without it has no fitting path, so do not assume every UCFL307 on site accepts relubrication.
- Self-aligning is not the same as free to move: the UC307D1 insert of UCFL307 pivots to correct static misalignment, but a continuously bending shaft still frets the spherical seat.
- The standard section of UCFL307 can look adequate at 35 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.
Frequently asked questions
What are the dimensions of an UCFL307 mounted bearing?
UCFL307 takes a 35 mm shaft (insert UC307D1, 80 mm OD) and has a unit mass of about 1.7 kg. Flange figures: height H 185 mm, length L 100 mm, bolt centres J 141 mm, holes 23 mm for M20 bolts.
What does the UCFL307 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 35 mm bore. UCFL307 is built from housing FL307 plus insert UC307D1 (D1 = greasable).
How is UCFL307 locked to the shaft, and how tight should the setscrews be?
The UC307D1 insert uses two collar setscrews on the 35 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 UCFL307 instead of a pillow block?
Choose the UCFL307 two-bolt flange when the 35 mm shaft meets a vertical frame or side plate: the diamond housing bolts flush with two M20 bolts on 141 mm centres. A UCP pillow block is used when the shaft runs above a horizontal mounting surface.
How often should I relubricate an UCFL307 unit?
There is no single interval for UCFL307: the UC307D1 insert is regreased through the D1 fitting while the shaft turns, using an NLGI 2 lithium or lithium-complex grease. Quarterly is typical for normal ambient conveyor duty; shorten to weekly or monthly where temperatures exceed about 70 °C, water is present, or dust is heavy.
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.