Two-Bolt Pillow Block Ball Bearing, 2-1/16 in Bore, Cast Iron, Setscrew Locking, Relubricatable

What this part is:
The P3U233H is a two-bolt PILLOW BLOCK ball bearing unit with a 2-1/16 in (52.39 mm) bore in a cast iron housing. Note the housing form, because Link-Belt numbering is often misread: the P3U prefix is a base-mounted pillow block from the P3U200 series, NOT a flange block. It bolts down through two slotted feet in the base and carries the shaft parallel to the mounting surface. If you need the shaft to run perpendicular to a bulkhead or gearbox face, you want an F-prefix Link-Belt flange block instead, not this.

Decoding the designation:
Bore sizing follows Link-Belt’s inch code, which steps in sixteenths: 223 is 1-7/16 in, 231 is 1-15/16 in, and 233 is 2-1/16 in. Getting this wrong by one code step is a 1/16 in error that will not mount, so check the code against the shaft rather than the nominal description.

What these specs mean in practice:
The insert is a wide-inner-ring ball bearing locked to the shaft by setscrews through the extended inner ring. Setscrew locking is the quick, serviceable option — it drops onto a plain, undersized shaft with no shoulder, retaining ring or interference fit, and it comes off again without a press. The trade-off against an eccentric or concentric collar is that setscrews can back off and can burr the shaft under heavy reversing or shock load, so on a driven shaft that reverses direction, consider a collar-locked unit and always torque the screws to the plate instructions.

Installation and setup notes:
The housing carries a grease fitting, so the unit is relubricatable in service rather than sealed-for-life — worth planning a grease route to it if the mounting is buried. Pillow blocks locate the shaft axially through the insert, so on a long shaft that will grow with temperature, fix one end and use an expansion unit at the other to avoid thermally preloading the bearings.

Quantity and configuration:
Supplied as a complete housed assembly: cast iron housing, insert and setscrews, ready to bolt down.

Interchange guidance:
Link-Belt bearings passed from the Rexnord Link-Belt Bearing Division to Regal Rexnord, so current-catalogue equivalents cross to Rexnord and Regal Rexnord numbers — buyers keeping older Link-Belt plant running usually search the legacy number, which is why both forms are listed here. Also written P3-U233H, P3U-233-H and P3U 233 H.