UCP310 bearing: complete specifications & equivalents
The UCP310 is a JIS B 1559 radial bearing sized 50 x 110 x 61 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 | 50 mm |
| Outer diameter D | 110 mm |
| Width B | 61 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 68.5 kN |
| Basic static load rating C0 | 38.5 kN |
| Fatigue load limit Pu | 2.99 kN |
| Mass | 5600 g |
| Housing height H | 75 mm |
| Housing overall length L | 275 mm |
| Mounting bolt center distance J | 212 mm |
| Mounting hole diameter N | 20 mm |
| Manufacturer designation | UCP310 |
| 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 | 1.969 in |
|---|---|
| Outer diameter D | 4.331 in |
| Width B | 2.402 in |
| ISO bore code | 10 |
| Radial section height (D−d)/2 | 30 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) | 10 of 25 |
| Bore above smallest UCP-series size | 38 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCP310 | 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 UCP310 model number is decoded
In NTN's mounted-ball-bearing range, UCP310 is the classic upright pillow block for a 50 mm shaft: insert UC310D1, housing P310, two foundation bolts. The UCP310 number follows NTN's mounted-unit convention: housing letter P, 3-series section, bore code for 50 mm; P310 and UC310D1 are the separate housing and insert part numbers inside. Shaft size is 50 mm; the cast base stands 75 mm to the shaft centre (H), is 275 mm long overall (L), and the two foundation holes on 212 mm centres (J) clear 20 mm M16 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. Most general industrial shafting in the 25–50 mm range ends up on exactly this class of unit: designers trade the 2, X and 3 sections against conveyor centres and belt tension rather than against absolute capacity. Small marine and dockside conveyors use this unit with stainless fasteners through the feet; the cast iron tolerates salt atmosphere far better than pressed-steel housings once paint is chipped. In wet or washdown positions, orient the grease fitting at 45° and purge after every wash; water trapped between the slinger and lip seal emulsifies the grease even when the unit is sealed. Basic ratings of the UC310D1 insert are 68.5 kN dynamic and 38.5 kN static; the assembled UCP310 weighs about 5.6 kg.
Typical equipment & failure modes
Common applications
- agricultural augers and bucket elevators
- small crushers and screening feeds
- textile line-shafting
- long line-shafting where several units must share a straight reference
Known failure patterns
- 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
- spherical-seat fretting that welds insert to housing and destroys the self-aligning action
Selection pitfalls — read before you substitute
- UCP310 is located on the shaft by setscrews only; for shock reversing drives consider an adapter-lock insert family instead, since setscrew points indent the 50 mm journal over time.
- With a 50 mm shaft the M16 foundation bolts of UCP310 must be re-checked after run-in — paint crush under the feet is enough to loosen both the feet and the setscrews.
- The 3-series insert makes UCP310 the highest-rated unit at 50 mm; its advantage disappears on a soft foundation, so spend the saved margin on base stiffness rather than skipping shims.
- As a pillow block, UCP310 needs a prepared horizontal surface at the 75 mm centre height: shim both feet with full-width packs so the 275 mm base seats over its full area.
Frequently asked questions
How is UCP310 locked to the shaft, and how tight should the setscrews be?
The UC310D1 insert uses two collar setscrews on the 50 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 UCP310 instead of a flanged unit?
Choose the UCP310 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 75 mm above the 275 mm bolt-down base. Choose a UCFL flange when the shaft meets a vertical frame face and the housing bolts flat against it.
What are the dimensions of an UCP310 mounted bearing?
UCP310 takes a 50 mm shaft (insert UC310D1, 110 mm OD) and has a unit mass of about 5.6 kg. Housing figures: centre height H 75 mm, length L 275 mm, bolt centres J 212 mm, foot holes 20 mm for M16 bolts.
What does the UCP310 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 50 mm bore. UCP310 is built from housing P310 plus insert UC310D1 (D1 = greasable).
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.