UCF208 Bearing Dimensions

UCF208 compared with nearby sizes and housings

UCF208 is a square flange unit that holds the UC208 insert on a 40 mm shaft: flange length L 132 mm (JIS maximum) with M14 bolts.

The same 208 size is also made as UCP208 (pillow block unit, d 40 · H 49.2 · J 137 mm), UCFL208 (oval flange unit, d 40 · L 175 · J 144 mm) and UCFC208 (round flange unit, d 40 · D2 145 · P 120 mm). All of them take the same UC208 insert, so a worn insert can be changed without changing the housing type.

UCF209 is the next larger size in the same series on this site: shaft d 45 mm (5 mm more), inner ring width B 49.2 mm (the same) and bolt spacing J 105 mm (3 mm more).

UCF207 is the next smaller size in the same series on this site: shaft d 35 mm (5 mm less), inner ring width B 42.9 mm (6.3 mm less) and bolt spacing J 92 mm (10 mm less), and it takes M12 bolts instead of M14.

Dimensions in mm from the model pages; weight from FULI's catalog, — = not listed on this site.

UCF208 weight, load ratings and speed

FULI's catalog gives about 1.9 kg for the complete unit, housing and insert together, so 100 pieces of UCF208 weigh about 190 kg before packing.

The catalog lists UCF208 with a dynamic load rating of 29.1 kN and a static load rating of 17.9 kN. Its speed limits depend on the shaft tolerance: 3,600 rpm on a js7 or j7 shaft and 2,600 rpm on an h7 shaft. A closer shaft fit holds the inner ring more evenly, which is why the js7 / j7 figure is higher.

Values from FULI's catalog; confirm for your application.

UCF208 dimensions in inches

The nearest common inch shaft size to the 40 mm bore of UCF208 is 1-9/16 in (39.69 mm), 0.31 mm smaller than the bore, so UCF208 would be loose on it. An inch shaft needs an inch bore insert. FULI also makes UCF208 with inch bores: UCF208-24 for a 1-1/2 in shaft (38.10 mm) and UCF208-25 for a 1-9/16 in shaft (39.69 mm). The outside dimensions stay the same as the metric UCF208.

Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.

Mounting UCF208 (general guidance)

General guidance, not a FULI specification: insert bearings slide onto the shaft rather than being pressed on, and are held by their locking device. A shaft ground or drawn to h7 is common; a closer shaft such as js7 or j7 suits higher speed. For UCF208 the catalog gives 3,600 and 2,600 rpm for the two cases.

The UC208 insert in UCF208 is locked by set screws in the extended inner ring. Housed-unit problems usually start at the set screws: if the inner ring is not held, it turns on the shaft and wears it. Tighten each screw to the torque in the mounting instructions, and check them again after the first hours of running.

Bolt UCF208 down with M14 bolts at 102 mm spacing on a flat, rigid face. Line up the two housings on a shaft before tightening the bolts fully, then lock the inserts, so the shaft is not bent between them.

Grease for UCF208

The insert in UCF208 is sealed on both sides and greased at the factory. If the housing has a grease fitting, add grease slowly through it while the shaft turns until a little fresh grease shows at the seals; general practice is to relubricate more often in wet or dusty places.

Greases for a stated temperature range can be specified on the order; for North America a range of −40 to 120 °C is often asked for.

How FULI supplies UCF208

FULI supplies UCF208 as a complete unit, or the UC208 insert on its own for replacement. Before packing, the factory checks the mounting torque, the fit of the insert in the housing, the radial clearance and that the base-to-centre height is consistent across the batch.

Rings are marked with a brand you are authorised to use, with the FULI brand, or left neutral, as your order states. The box is printed with the model, precision class and brand.

Inquiries that leave out the prefix or suffix letters are the usual cause of a wrong quote, so write the full designation, for example UCF208 or UCF208-24 for the inch bore.

Tools and guides for UCF208

• Insert bearing sizes: UC, SB and SA
• Pillow block bearing sizes
• Flange bearing sizes
• Pillow block bearing cross reference
• Inch bore pillow block bearings
• Bearing lubrication basics
• All bearing products and model pages