UC204 Bearing Dimensions
UC204 insert bearing: 20 mm bore, 47 mm spherical OD, 31 mm width, set-screw lock (FULI catalog). Fits P204/F204/FL204/T204 housings. Quote.
UC204 specifications
| Bore d | 20 mm |
|---|---|
| Outside diameter D | 47 mm |
| Inner ring width B | 31 mm |
| Seal / shield options | Sealed insert bearing (UC type), spherical outside diameter, set-screw locking |
| Material | GCr15 chrome bearing steel (rings and rolling elements) |
| Precision | P0 (standard) |
| Radial clearance | C0 (standard); C3 on request |
Dimensions from FULI's catalog.
Load ratings & speed
| Dynamic load rating Cr | 12.8 kN |
|---|---|
| Static load rating C0r | 6.6 kN |
| Limiting speed, shaft js7 / j7 | 6,700 rpm |
| Limiting speed, shaft h7 | 4,900 rpm |
| Weight | 0.17 kg — approx. |
Values from FULI's catalog; confirm for your application.
Inch bore versions
| Metric model | Inch model | Bore (in) | Bore (mm) |
|---|---|---|---|
| UC204 | UC204-12 | 3/4" | 19.05 |
Inch bore versions have the same outside diameter and ring widths as the metric UC204; only the bore is different. Write the inch designation on your order, for example UC204-12.
How to read the UC204 designation
| Segment | Meaning |
|---|---|
| UC | Insert bearing with set-screw locking and spherical outside diameter |
| 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). |
UC204 interchange
UC204 is an ISO designation. The boundary dimensions are identical across manufacturers; only suffixes (seals, clearance, cage) differ.
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.
UC204 compared with nearby sizes and housings
UC204 is a set-screw insert for a 20 mm shaft: outside diameter 47 mm, inner ring width 31 mm.
The UC204 insert is the one fitted in UCP204 (pillow block unit), UCF204 (square flange unit) and UCFL204 (oval flange unit). Other inserts with the same size code are SB204 (20 × 47 × 25 mm) and SA204 (20 × 47 × 21.5 mm).
UC205 is the next larger size in the same series on this site: shaft d 25 mm (5 mm more), outside diameter D 52 mm (5 mm more) and inner ring width B 34.1 mm (3.1 mm more).
UC203 is the next smaller size in the same series on this site: shaft d 17 mm (3 mm less), outside diameter D 47 mm (the same) and inner ring width B 31 mm (the same).
| Model | Type | Main dimensions | Weight (kg) |
|---|---|---|---|
| UC204 | insert bearing (this page) | 20 × 47 × 31 mm (d × D × B) | 0.17 |
| UC203 | insert bearing | 17 × 47 × 31 mm (d × D × B) | — |
| UC205 | insert bearing | 25 × 52 × 34.1 mm (d × D × B) | 0.21 |
| 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 |
| UCF204 | square flange unit | d 20 · L 86 · J 64 mm | — |
| 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.
UC204 weight, load ratings and speed
FULI's catalog gives about 0.17 kg for the insert, so 100 pieces of UC204 weigh about 17 kg before packing.
The catalog lists UC204 with a dynamic load rating of 12.8 kN and a static load rating of 6.6 kN. Its speed limits depend on the shaft tolerance: 6,700 rpm on a js7 or j7 shaft and 4,900 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.
UC204 dimensions in inches
The nearest common inch shaft size to the 20 mm bore of UC204 is 13/16 in (20.64 mm), 0.64 mm larger than the bore, so UC204 will not go on it. An inch shaft needs an inch bore insert. FULI also makes UC204 with inch bores: UC204-12 for a 3/4 in shaft (19.05 mm). The outside dimensions stay the same as the metric UC204.
| Dimension | Millimetres | Inches |
|---|---|---|
| Bore d | 20 mm | 0.7874 in |
| Outside diameter D | 47 mm | 1.8504 in |
| Inner ring 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 UC204 (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 UC204 the catalog gives 6,700 and 4,900 rpm for the two cases.
UC204 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.
The spherical outside diameter of UC204 lets the insert swivel in the housing seat while it is being mounted, which takes up small errors in shaft line. It does not make the bearing a self-aligning bearing in service.
Grease for UC204
The insert is sealed on both sides and greased at the factory. Fitted in a housing with a grease fitting, it can be relubricated through the housing; on its own it runs on the factory fill.
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 UC204
FULI supplies UC204 on its own as a replacement insert, or fitted in a housing as a complete unit. The rings and balls are GCr15 chrome steel and the radial clearance is C0 as standard, with C3 on request.
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 UC204 or UC204-12 for the inch bore.
Tools and guides for UC204
Typical applications
- Replacement inserts for UCP / UCF / UCFL housings
- Conveyors
- Agricultural machinery
FAQ
What shaft size does UC204 fit?
A 20 mm shaft (0.7874 in). For inch shafts the same size is made as UC204-12 (3/4 in).
What is the difference between UC204 and UC205?
UC205 is the next size up, for a 25 mm shaft, with outside diameter D 52 mm (5 mm more) and inner ring width B 34.1 mm (3.1 mm more). Choose UC205 when the shaft is larger or the load is higher; the housings are not interchangeable.
Which housings fit the UC204 insert?
UCP204 (pillow block unit), UCF204 (square flange unit) and UCFL204 (oval flange unit) all use UC204. Order UC204 on its own to replace a worn insert in any of them.
What is the difference between UC204 and SB204?
Both fit a 20 mm shaft with a 47 mm outside diameter. UC204 has an inner ring 31 mm wide and SB204 25 mm. Both lock with set screws. Check that the narrower or wider ring clears the housing and the parts beside it on the shaft.
How much does UC204 weigh?
About 0.17 kg in FULI's catalog; 100 pieces weigh about 17 kg before packing.
Can UC204 be ordered as an insert only, or as a complete unit?
Both. UC204 can be supplied on its own as a replacement insert for an existing housing, or fitted in a housing such as the UCP204 pillow block or UCF204 square flange and supplied as a complete unit. Tell us which you need when you send the inquiry.