1 Inch Pillow Block Bearing
Convert shaft or bearing dimensions between mm and inch and see the closest standard bore: 25 mm UC205 vs 1 inch UC205-16, 3/4 inch, 1-1/4 inch and more.
Convert a shaft diameter between millimetres and inches, then check whether a metric or an inch-bore insert is the closer match.
Common shaft sizes, mm to inch
| mm | Inch (decimal) | Nearest standard inch fraction |
|---|---|---|
| 19.05 | 0.750 | 3/4 in |
| 22.225 | 0.875 | 7/8 in |
| 25.4 | 1.000 | 1 in |
| 28.575 | 1.125 | 1-1/8 in |
| 31.75 | 1.250 | 1-1/4 in |
| 34.925 | 1.375 | 1-3/8 in |
| 38.1 | 1.500 | 1-1/2 in |
| 44.45 | 1.750 | 1-3/4 in |
These are the standard inch shaft sizes used across the bearing industry; they do not line up exactly with the metric bore steps (20, 25, 30, 35 mm and so on), which is why a shaft must be machined to one system or the other.
Inch bore suffix on UC inserts
The digits after the hyphen on an insert number are the bore in sixteenths of an inch: -12 is 3/4 inch (19.05 mm), -16 is 1 inch (25.4 mm), -20 is 1-1/4 inch (31.75 mm), -24 is 1-1/2 inch (38.1 mm). The number before the hyphen (such as 205) still tells you the outside diameter and housing fit — UC205-16 has the same 52 mm outside diameter and 34.1 mm width as the metric UC205, just with a 1 inch bore instead of 25 mm. See insert bearing for the metric size range this is based on.
Checking a size
- Measure the shaft in mm or inches.
- If the shaft is a standard metric size (20, 25, 30, 35, 40, 45 mm), use the matching UC2xx insert — see the shaft size to mounted bearing selector.
- If the shaft is a standard inch size, convert it to mm with the table above, find the nearest UC2xx frame size by outside diameter, and order the inch-bore version of that frame with the -xx suffix.
Send the exact shaft diameter, in mm or inches, to sales@fuli-bearings.com or use the request a quote form to confirm availability for that specific inch size.
FAQ
What does the -16 mean in UC205-16?
It is the bore in sixteenths of an inch: 16/16 = 1 inch. The same system gives -12 for 3/4 inch, -20 for 1-1/4 inch and -24 for 1-1/2 inch. The number before the hyphen (205) is still the housing-fit size, not the bore.
Does an inch insert fit the same housing as the metric size of the same number?
Yes. An inch bore insert such as UC205-16 has the same outside diameter and ring widths as the metric UC205 — only the bore is cut to the inch dimension — so it fits the same UCP205, UCF205 or UCFL205 housing.
Is 25 mm close enough to 1 inch to use interchangeably?
No, not for the bearing bore itself: 1 inch is 25.4 mm, 0.4 mm larger than 25 mm, which is enough difference that a shaft must be made to the one or the other, not both. Order UC205 for a 25 mm shaft and UC205-16 for a 1 inch shaft.