UCFL321 Bearing Dimensions
UCFL321 2-bolt oval flange bearing unit: 105 mm bore, 360 mm bolt centres. FL321 housing + UC321 insert, designation, size-equivalent codes.
UCFL321 specifications
| Shaft diameter d | 105 mm |
|---|---|
| Flange length L | 440 mm |
| Bolt hole spacing J | 360 mm |
| Flange width H | 270 mm |
| Insert width B | 112 mm |
| Mounting bolt | M39 |
| 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.
How to read the UCFL321 designation
| Segment | Meaning |
|---|---|
| UC | Insert bearing with set-screw locking and spherical outside diameter |
| FL | Two-bolt oval flange housing |
| 3 | 300 series (medium duty) |
| 21 | Bore code 21 → 105 mm bore. ISO bore code (00–03 = 10/12/15/17 mm; 04 and above = code × 5 mm). |
UCFL321 interchange
UCFL321 is a housed unit: a UC321 insert bearing in an FL321 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.
UCFL321 compared with nearby sizes and housings
UCFL321 is a oval flange unit that holds the UC321 insert on a 105 mm shaft: flange length L 440 mm and flange width H 270 mm with M39 bolts.
The same 321 size is also made as UCP321 (pillow block unit, d 105 · H 140 · J 380 mm). All of them take the same UC321 insert, so a worn insert can be changed without changing the housing type.
UCFL326 is the next larger size in the same series on this site: shaft d 130 mm (25 mm more), inner ring width B 135 mm (23 mm more), length L 550 mm (110 mm more) and bolt spacing J 460 mm (100 mm more), and it takes M42 bolts instead of M39.
| Model | Type | Main dimensions | Weight (kg) |
|---|---|---|---|
| UCFL321 | oval flange unit (this page) | d 105 · L 440 · J 360 mm | — |
| UCFL326 | oval flange unit | d 130 · L 550 · J 460 mm | — |
| UC321 | insert bearing | 105 × 225 × 112 mm (d × D × B) | — |
| UCP321 | pillow block unit | d 105 · H 140 · J 380 mm | — |
Dimensions in mm from the model pages; weight from FULI's catalog, — = not listed on this site.
UCFL321 load ratings
FULI's catalog has no load rating line for UCFL321 itself, so none is given here. The ratings of the UC321 insert are on its own page. Ask us and we send the figures with the quotation.
UCFL321 dimensions in inches
The nearest common inch shaft size to the 105 mm bore of UCFL321 is 4-1/8 in (104.78 mm), 0.22 mm smaller than the bore, so UCFL321 would be loose on it. An inch shaft needs an inch bore insert. Inch bore versions are made for some sizes; ask us with the shaft size.
| Dimension | Millimetres | Inches |
|---|---|---|
| Shaft diameter d | 105 mm | 4.1339 in |
| Flange length L | 440 mm | 17.3228 in |
| Bolt hole spacing J | 360 mm | 14.1732 in |
| Flange width H | 270 mm | 10.6299 in |
| Insert width B | 112 mm | 4.4094 in |
Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.
Mounting UCFL321 (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 UC321 insert in UCFL321 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 UCFL321 down with M39 bolts at 360 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 UCFL321
The insert in UCFL321 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 UCFL321
FULI supplies UCFL321 as a complete unit, or the UC321 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 UCFL321.
Tools and guides for UCFL321
Typical applications
- Conveyors
- Packaging machinery
- Agricultural machinery
- Textile machinery
FAQ
What shaft size does UCFL321 fit?
A 105 mm shaft (4.1339 in).
What is the difference between UCFL321 and UCFL326?
UCFL326 is the next size up, for a 130 mm shaft, with inner ring width B 135 mm (23 mm more), length L 550 mm (110 mm more) and bolt spacing J 460 mm (100 mm more). It takes M42 bolts. Choose UCFL326 when the shaft is larger or the load is higher; the housings are not interchangeable.
Which insert fits UCFL321?
The UC321 insert (105 × 225 × 112 mm). It is sold on its own for replacement.
UCFL321 or UCP321: which should I use?
Both hold the same UC321 insert on a 105 mm shaft. UCFL321 is a oval flange unit (d 105 · L 440 · J 360 mm); UCP321 is a pillow block unit (d 105 · H 140 · J 380 mm). 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 UCFL321 come as a complete unit or insert only?
UCFL321 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 UCFL321?
Load ratings for UCFL321 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.