UCF204 Bearing Dimensions
UCF204 4-bolt square flange bearing unit: 20 mm bore, 64 mm bolt centres. F204 housing + UC204 insert, designation, size-equivalent codes.
UCF204 specifications
| Shaft diameter d | 20 mm |
|---|---|
| Flange length L | 86 mm |
| Bolt hole spacing J | 64 mm |
| Insert width B | 31 mm |
| Mounting bolt | M10 |
| Seal / shield options | Sealed insert bearing (UC type) with cast iron housing |
| Material | Insert: GCr15 chrome bearing steel (rings and rolling elements); housing: cast iron |
| Precision | P0 (standard) |
| Radial clearance | C0 (standard); C3 on request |
| Load ratings | Load ratings for this model are being checked against FULI's catalog. Ask for them with the quote. |
Dimensions cross-checked against published catalogues; please confirm with your quote.
Inch bore versions
| Metric model | Inch model | Bore (in) | Bore (mm) |
|---|---|---|---|
| UCF204 | UCF204-12 | 3/4" | 19.05 |
Inch bore versions use the same housing and outer dimensions as the metric UCF204; only the bore is different. The dimensions above and the JIS / ISO bolt spacing note under Interchange apply to both. Write the inch designation on your order, for example UCF204-12.
How to read the UCF204 designation
| Segment | Meaning |
|---|---|
| UC | Insert bearing with set-screw locking and spherical outside diameter |
| F | Four-bolt square flange housing |
| 2 | 200 series (light duty) |
| 04 | Bore code 04 → 20 mm bore. ISO bore code (00–03 = 10/12/15/17 mm; 04 and above = code × 5 mm). |
UCF204 interchange
UCF204 is a housed unit: a UC204 insert bearing in an F204 housing. The insert bearing dimensions follow ISO and interchange between manufacturers. Housing dimensions such as bolt hole spacing can differ between the JIS and ISO versions of the same designation, so please confirm the mounting dimensions with us before ordering.
Brand numbers for UCP, UCF and UCFL units: Pillow Block Bearing Cross Reference.
Brand names are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by these companies. Part numbers are shown for interchange reference only. FULI dimensions, load ratings and speeds come from the FULI catalog.
UCF204 compared with nearby sizes and housings
UCF204 is a square flange unit that holds the UC204 insert on a 20 mm shaft: flange length L 86 mm with M10 bolts.
The same 204 size is also made as UCP204 (pillow block unit, d 20 · H 33.3 · J 95 mm (JIS)) and UCFL204 (oval flange unit, d 20 · L 113 · J 90 mm). All of them take the same UC204 insert, so a worn insert can be changed without changing the housing type.
UCF205 is the next larger size in the same series on this site: shaft d 25 mm (5 mm more), inner ring width B 34.1 mm (3.1 mm more) and bolt spacing J 70 mm (6 mm more).
| Model | Type | Main dimensions | Weight (kg) |
|---|---|---|---|
| UCF204 | square flange unit (this page) | d 20 · L 86 · J 64 mm | — |
| UCF205 | square flange unit | d 25 · J 70 mm (JIS) | 0.9 |
| UC204 | insert bearing | 20 × 47 × 31 mm (d × D × B) | 0.17 |
| SB204 | insert bearing | 20 × 47 × 25 mm (d × D × B) | — |
| SA204 | insert bearing | 20 × 47 × 21.5 mm (d × D × B) | — |
| UCP204 | pillow block unit | d 20 · H 33.3 · J 95 mm (JIS) | 0.7 |
| UCFL204 | oval flange unit | d 20 · L 113 · J 90 mm | — |
Dimensions in mm from the model pages; weight from FULI's catalog, — = not listed on this site.
UCF204 load ratings
FULI's catalog has no load rating line for UCF204 itself, so none is given here. The ratings of the UC204 insert are on its own page. Ask us and we send the figures with the quotation.
UCF204 dimensions in inches
The nearest common inch shaft size to the 20 mm bore of UCF204 is 13/16 in (20.64 mm), 0.64 mm larger than the bore, so UCF204 will not go on it. An inch shaft needs an inch bore insert. FULI also makes UCF204 with inch bores: UCF204-12 for a 3/4 in shaft (19.05 mm). The outside dimensions stay the same as the metric UCF204.
| Dimension | Millimetres | Inches |
|---|---|---|
| Shaft diameter d | 20 mm | 0.7874 in |
| Flange length L | 86 mm | 3.3858 in |
| Bolt hole spacing J | 64 mm | 2.5197 in |
| Insert width B | 31 mm | 1.2205 in |
Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.
Mounting UCF204 (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.
The UC204 insert in UCF204 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 UCF204 down with M10 bolts at 64 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 UCF204
The insert in UCF204 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 UCF204
FULI supplies UCF204 as a complete unit, or the UC204 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 UCF204 or UCF204-12 for the inch bore.
Tools and guides for UCF204
Typical applications
- Conveyors
- Packaging machinery
- Agricultural machinery
- Textile machinery
FAQ
What shaft size does UCF204 fit?
A 20 mm shaft (0.7874 in). For inch shafts the same size is made as UCF204-12 (3/4 in).
What is the difference between UCF204 and UCF205?
UCF205 is the next size up, for a 25 mm shaft, with inner ring width B 34.1 mm (3.1 mm more) and bolt spacing J 70 mm (6 mm more). Choose UCF205 when the shaft is larger or the load is higher; the housings are not interchangeable.
Which insert fits UCF204?
The UC204 insert (20 × 47 × 31 mm). It is sold on its own for replacement.
UCF204 or UCP204: which should I use?
Both hold the same UC204 insert on a 20 mm shaft. UCF204 is a square flange unit (d 20 · L 86 · J 64 mm); UCP204 is a pillow block unit (d 20 · H 33.3 · J 95 mm (JIS)). Choose by how the bearing is fixed to the machine: a pillow block bolts to a surface parallel to the shaft, a flange to a face across it.
Does UCF204 come as a complete unit or insert only?
UCF204 is normally supplied as a complete unit (insert bearing already fitted in the housing). The insert can also be quoted separately if you are replacing only the bearing.
Where are the load ratings for UCF204?
Load ratings for UCF204 are being checked against FULI's catalog and are not shown on this page yet. Model pages with a "Load ratings & speed" table carry values from FULI's catalog.