UC203 Bearing Dimensions
UC203 insert bearing: 17 mm bore, 47 mm spherical OD, 31 mm width, set-screw lock. Fits P203/F203/FL203/T203 housings. Quote.
UC203 specifications
| Bore d | 17 mm |
|---|---|
| Outside diameter D | 47 mm |
| Inner ring width B | 31 mm |
| Outer ring width C | 17 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 |
| 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 UC203 designation
| Segment | Meaning |
|---|---|
| UC | Insert bearing with set-screw locking and spherical outside diameter |
| 2 | 200 series (light duty) |
| 03 | Bore code 03 → 17 mm bore. ISO bore code (00–03 = 10/12/15/17 mm; 04 and above = code × 5 mm). |
UC203 interchange
UC203 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.
UC203 compared with nearby sizes and housings
UC203 is a set-screw insert for a 17 mm shaft: outside diameter 47 mm, inner ring width 31 mm and outer ring width 17 mm.
Other inserts with the same size code are SB203 (17 × 40 × 22 mm) and SA203 (17 × 40 × 19.1 mm).
UC204 is the next larger size in the same series on this site: shaft d 20 mm (3 mm more), outside diameter D 47 mm (the same) and inner ring width B 31 mm (the same).
UC202 is the next smaller size in the same series on this site: shaft d 15 mm (2 mm less), outside diameter D 47 mm (the same) and inner ring width B 31 mm (the same).
| Model | Type | Main dimensions | Weight (kg) |
|---|---|---|---|
| UC203 | insert bearing (this page) | 17 × 47 × 31 mm (d × D × B) | — |
| UC202 | insert bearing | 15 × 47 × 31 mm (d × D × B) | — |
| UC204 | insert bearing | 20 × 47 × 31 mm (d × D × B) | 0.17 |
| SB203 | insert bearing | 17 × 40 × 22 mm (d × D × B) | — |
| SA203 | insert bearing | 17 × 40 × 19.1 mm (d × D × B) | — |
Dimensions in mm from the model pages; weight from FULI's catalog, — = not listed on this site.
UC203 load ratings
FULI's catalog has no load rating line for UC203 itself, so none is given here. Ask us and we send the figures with the quotation.
UC203 dimensions in inches
The nearest common inch shaft size to the 17 mm bore of UC203 is 11/16 in (17.46 mm), 0.46 mm larger than the bore, so UC203 will not go 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 |
|---|---|---|
| Bore d | 17 mm | 0.6693 in |
| Outside diameter D | 47 mm | 1.8504 in |
| Inner ring width B | 31 mm | 1.2205 in |
| Outer ring width C | 17 mm | 0.6693 in |
Converted at 1 in = 25.4 mm and rounded to four decimals. The bearing itself is made to the millimetre sizes.
Mounting UC203 (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.
UC203 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 UC203 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 UC203
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 UC203
FULI supplies UC203 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 UC203.
Tools and guides for UC203
Typical applications
- Replacement inserts for UCP / UCF / UCFL housings
- Conveyors
- Agricultural machinery
FAQ
What shaft size does UC203 fit?
A 17 mm shaft (0.6693 in).
What is the difference between UC203 and UC204?
UC204 is the next size up, for a 20 mm shaft, with outside diameter D 47 mm (the same) and inner ring width B 31 mm (the same). Choose UC204 when the shaft is larger or the load is higher; the housings are not interchangeable.
What is the difference between UC203 and SB203?
Both fit a 17 mm shaft with a 47 mm outside diameter. UC203 has an inner ring 31 mm wide and SB203 22 mm. Both lock with set screws. Check that the narrower or wider ring clears the housing and the parts beside it on the shaft.
Can UC203 be ordered as an insert only, or as a complete unit?
Both. UC203 can be supplied on its own as a replacement insert for an existing housing, or fitted in a housing such as the UCP203 pillow block or UCF203 square flange and supplied as a complete unit. Tell us which you need when you send the inquiry.
Where are the load ratings for UC203?
Load ratings for UC203 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.