UCPX18 bearing: complete specifications & equivalents
The UCPX18 is a JIS B 1559 radial bearing sized 90 x 190 x 104 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 | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 104 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 121 kN |
| Basic static load rating C0 | 82 kN |
| Fatigue load limit Pu | 5.55 kN |
| Mass | 16000 g |
| Housing height H | 101.6 mm |
| Housing overall length L | 381 mm |
| Mounting bolt center distance J | 283 mm |
| Mounting hole diameter N | 27 mm |
| Manufacturer designation | UCPX18 |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 4.094 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 50 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) | 18 of 25 |
| Bore above smallest UCP-series size | 78 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCPX18 | 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 UCPX18 model number is decoded
In NTN's mounted-ball-bearing range, UCPX18 is the classic upright pillow block for a 90 mm shaft: insert UCX18D1, housing PX18, two foundation bolts. Reading the designation: UC marks the wide-inner-ring, setscrew-locking insert; P marks the upright pillow block housing; the X code identifies the duty series and the final two digits encode the 90 mm bore. Key mounting figures: centre height H = 101.6 mm, overall base length L = 381 mm, bolt-hole spacing J = 283 mm, and each of the two feet takes a 27 mm (M22) fastener for the 90 mm shaft. The X section is NTN’s intermediate-duty build: a wider UCX insert with a higher rating sits in a longer, sturdier housing than the 2-series unit at the same bore. 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-block and brick plants mount this size on mixer and feeder drives in abrasive dust; the optional cast-iron closing covers are fitted more often here than in any other industry. On a horizontal shaft fill the housing cavity to roughly one third; packed-full housings churn the grease, run hot and destroy the thickener long before the base oil oxidises. Basic ratings of the UCX18D1 insert are 121 kN dynamic and 82 kN static; the assembled UCPX18 weighs about 16.0 kg.
Typical equipment & failure modes
Common applications
- quarry feeder and transfer drives
- sawmill arbors and feed rolls
- cement and clinker handling
- fan drives where belt tension, not transmitted torque, sets the radial load
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 X insert of UCPX18 is wider and rated above the 2-series part at 90 mm, but it is not interchangeable with a 3-series unit in a damaged application — check the housing length and bolt centres before swapping.
- As a pillow block, UCPX18 needs a prepared horizontal surface at the 101.6 mm centre height: shim both feet with full-width packs so the 381 mm base seats over its full area.
- Self-aligning is not the same as free to move: the UCX18D1 insert of UCPX18 pivots to correct static misalignment, but a continuously bending shaft still frets the spherical seat.
- UCPX18 at 90 mm uses M22 bolts that need a torque wrench and a cross pattern; pulling one bolt first tips the 101.6 mm centre height and binds the insert.
Frequently asked questions
What are the dimensions of an UCPX18 mounted bearing?
UCPX18 takes a 90 mm shaft (insert UCX18D1, 190 mm OD) and has a unit mass of about 16.0 kg. Housing figures: centre height H 101.6 mm, length L 381 mm, bolt centres J 283 mm, foot holes 27 mm for M22 bolts.
What does the UCPX18 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; P the upright pillow block housing; X is the duty series; the last digits encode the 90 mm bore. UCPX18 is built from housing PX18 plus insert UCX18D1 (D1 = greasable).
How is UCPX18 locked to the shaft, and how tight should the setscrews be?
The UCX18D1 insert uses two collar setscrews on the 90 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 UCPX18 instead of a flanged unit?
Choose the UCPX18 pillow block when the shaft runs parallel to a horizontal base plate, rail or plinth — the upright housing holds the shaft centre 101.6 mm above the 381 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.