NTNUCP201-008D1Two-Bolt Pillow Block Bearing Unit, 1/2″ Bore, Setscrew Locking, Nitrile Contact Seals, Relubricatable

Product Description

What this part is

An NTN UCP201-008D1 mounted ball bearing unit — a two-bolt cast iron pillow block for a 1/2 in shaft. A UC-type wide-inner-ring insert with a spherical outer race sits self-aligning in a one-piece cast iron housing and locks to the shaft with setscrews in the extended inner ring. In NTN’s scheme the assembly is built from bearing UC201-008D1 in housing P203D1.

Decoding the designation

UC – wide inner ring insert, spherical outer race, setscrew locking
P – pillow block housing. NTN’s flange styles are UCFU (four-bolt square) and UCFL (two-bolt oval); UCP is a pillow block and mounts to a surface parallel with the shaft
201 – light-duty 200-series envelope
008 – bore in sixteenths of an inch, so 8/16 = 1/2 in
D1 – relubricatable with grease fitting

Correcting the source data

Earlier copy called this a flange mount unit. It is a pillow block: it bolts down onto a base parallel with the shaft, on two bolts at 3-3/4 in centres. A UCFU or UCFL housing bolts to a face perpendicular to the shaft and is not a substitute.

Published ratings and mounting data

Shaft size (d): 0.5000 in / 12.700 mm
Bolt hole centres (J): 3.7500 in / 95.0 mm · bolt hole size (N): 0.5000 in, slot 0.6250 in
Base to shaft centre height (H): 1.1875 in / 30.2 mm · overall height (H2): 2.4375 in / 62.0 mm
Overall length (L): 5.0000 in / 127.0 mm · base width (A): 1.5000 in / 38.0 mm · base thickness (H1): 0.5625 in
Insert width (B): 1.2205 in / 31.000 mm · inner ring extension (S): 0.5000 in · F: 0.1850 in
Basic dynamic load rating: 12.80 kN / 2,878 lbf
Basic static load rating: 6.65 kN / 1,495 lbf
Weight: 1.572 lb / 0.710 kg
Housing: cast iron, one piece, light duty, open end · Seals: contact, nitrile rubber
Lubrication: relubricatable · Operating temperature: −40 to 250 °F (−40 to 120 °C)

What these specs mean in practice

Setscrew locking on an extended inner ring is the fastest mounted-bearing fit there is and the easiest to service, but it marks the shaft and it is happiest under steady, largely unidirectional load. Reversing drives and heavy shock favour an eccentric collar or a concentric clamping unit. The nitrile contact seals keep out dust and splash and are good for general indoor duty, not high-pressure wash-down.

The spherical outer race lets the insert swivel in the housing, so the unit tolerates modest angular misalignment between the mounting surface and the shaft — the reason pillow blocks like this suit fabricated frames and conveyor rails where machined alignment is not realistic. This is a light-duty 201-series envelope; if the load path is heavy or shock-prone, step up to a 205/206-series unit rather than relying on the same bore size.

Quantity and configuration

One complete unit — P203D1 cast iron housing with the UC201-008D1 insert, seals, setscrews and grease fitting installed. No shaft, no mounting bolts.

Fitting notes

Check 3-3/4 in bolt centres and 1-3/16 in centre height against the frame you are replacing into. Slide the unit onto a clean shaft, let the insert find its alignment by turning the shaft, then tighten both setscrews evenly. Only one bearing on a shaft should be axially located; if the shaft grows thermally, use a wide-inner-ring insert with clearance at the far end.

Interchange guidance

The UCP201-008 footprint is a widely adopted industry pattern, so same-size two-bolt setscrew pillow blocks from other makers usually share the 3-3/4 in bolt centres and 1-3/16 in centre height — still worth verifying before you commit. UCFU201-008 and UCFL201-008 use the same insert in flange housings; they are related units, not interchange for this housing.