Pillow Block Bearing

A pillow block bearing is a bearing unit that bolts to a flat base parallel to the shaft: a sealed ball bearing insert sits in a cast iron block, so the unit goes onto a frame without machining a bearing seat. FULI is a pillow block bearing manufacturer and supplier in Linqing, Shandong, and our factory makes the UCP units on this page; our bearing manufacturer page shows the other types we make. The size table above lists every UCP model on this site with its bore, insert width, centre height and bolt spacing. Below: what the letters in a pillow block designation mean, how to read the dimensions, and what to send with an inquiry.

Pillow block bearing range and series at FULI

The UCP 200 series is the light duty pillow block series, covering 20 to 60 mm bores on this site (UCP204 to UCP212). Each unit is a UC insert, a deep groove ball bearing with a spherical outside diameter, an extended inner ring and two set screws that lock it to the shaft, in a P block cast in one piece with a two-bolt base. The spherical seat lets the insert align itself, which takes up small mounting errors.

In the size table above, UCP207 and UCP209 to UCP212 values are from FULI’s catalog. UCP205, UCP206 and UCP208 values are cross-checked against FULI’s catalog and published manufacturer datasheets. UCP204 follows the JIS B 1557 standard sizes until our factory drawing is added. The full UCP 200, UCP 300 and UKP lists from the catalog are in the catalog size tables further up the page, and units that run in a sliding frame are on the take up bearing page. The UCP bearing size chart adds base length L for the same models.

Type of pillow block bearing

Pillow block bearing types are told apart by two things: the housing and the way the insert locks to the shaft. In the designation, the first letters name the insert and the next letter names the housing:

Segment	Meaning in UCP205
UC	UC insert with set-screw locking and spherical outside diameter
P	Pillow block housing with a two-bolt base
2	200 series (light duty)
05	Bore code: 05 × 5 = 25 mm bore

The same UC insert also goes into flange housings; a UCF205 uses the same UC205 insert as a UCP205 in a four-bolt square flange. If you need a housing style or series that is not listed on this site, send the designation and we will confirm it with the quote.

Pillow block bearing dimensions and size

A pillow block bearing size is read from five numbers. The bore d matches the shaft. The centre height H runs from the bottom of the base to the bore centre, and it decides whether the unit lines up with the rest of the drive. The bolt hole spacing J is the distance between the two mounting bolts, and the base length L is the overall length of the foot. The insert width B tells you how much axial length the unit takes up.

When you replace a unit, measure the shaft and the bolt spacing first. Two units with the same designation can differ in bolt spacing if one is made to JIS and the other to ISO 3228, so compare J against your frame before ordering. Each model page gives the full dimension set, the mounting bolt size and, where published, FULI’s catalog load ratings.

How the unit works

The block holds the outer ring of the insert while the inner ring turns with the rotating shaft, and the balls between them carry radial and limited axial loads with low friction. That covers most shaft support jobs on conveyors and farm equipment.

Pillow block bearing advantages

• Easy mounting. Two bolts to a flat surface; no bore to cut in the frame.
• Self-aligning. The spherical seat takes up small misalignment as the bolts are tightened.
• Replaceable insert. A worn insert can be changed without replacing the block.
• Sealed and greased. The insert arrives sealed on both sides and filled with grease.

How to choose a pillow block bearing

1. Bore. For codes 04 and up, the bore code times five gives the bore in millimetres: UCP208 has a 40 mm bore.
2. Load. The 200 series is light duty. The 300 series, such as UCP321, uses a larger insert for the same bore and suits heavy loads and shock. For heavy-duty applications beyond that, the usual step up is a split block with a spherical roller bearing. Our pillow block vs plummer block guide compares the two.
3. Locking mechanisms. UC inserts lock with set screws; other types use an eccentric collar or a tapered adapter sleeve (the UKP units in the catalog tables).
4. Mounting options. Compare centre height H and bolt spacing J with the frame. A UCPH raises the centre line; a UCPA has a solid base with tapped holes.

Where pillow blocks are used

Typical uses are conveyor systems, agricultural equipment, fans and blowers, food processing lines and other industrial equipment. See conveyor bearings and agricultural machinery bearings for the sizes used there. The name pillow block is also used for linear bearing units that run on a rail or linear slide; those are a different product.

Lubrication and seals

Standard UCP blocks have a grease fitting on top for relubrication. In dusty, damp or hot service, add a little grease at regular checks so fresh grease pushes dirt out past the seals; do not overfill. Grey cast iron is painted to slow corrosion. For washdown areas and other harsh environments, stainless steel or thermoplastic units give better corrosion resistance, so state the environment in the inquiry.

Inch bore pillow block bearings

Our factory also makes inch bore versions of these units. The number after the dash is the bore in sixteenths of an inch, so UCP205-16 fits a 1 inch shaft and UCP208-24 fits a 1-1/2 inch shaft. The housing is the same as the metric unit of the same size; only the bore is different. See the inch bore pillow block bearing page for every inch size with its bore in millimetres.

Specifications FULI supplies

Item	FULI specification
Series	UCP 200, metric and inch bore
Insert	UC type, sealed, spherical outside diameter, set-screw locking
Insert material	GCr15 chrome bearing steel, rings and rolling elements
Housing	Cast iron, two-bolt base
Precision	P0 standard
Radial clearance	C0 standard; C3 on request
Supply	Complete unit; insert or housing quoted separately on request

Mounting bolt torque: a cast iron housing foot can crack below the torque a bolt chart gives for the bolt size. In 2017 some P208 housings we shipped to Chile cracked at the bolt holes on site, and we replaced the units by air freight, free of charge. Since then we test more samples before giving a torque figure and give it with a margin: 18 N·m for P208 housings with M14 bolts. The full story and the checks to make on site are in the pillow block installation checklist.

To get a quotation, send the designation (for example UCP205 or UCP205-16), the quantity per size and the destination port to sales@fuli-bearings.com or use the request a quote form.