UCP205, UCP305, UCPX05 - Same shaft size, different bearings

Firstly, if you have come here wanting to buy any of these three bearings then please follow the links below :
UCP205 Pillow block bearing
UCP305 Pillow block bearing
UCPX05 Pillow block bearing
This page contains information about the bearings and compares their respective features and we are  going to be looking at the differences between pillow block bearing manufacturers for these items.

We have chosen to look at these 3 bearings as they all have the same basic housing and insert bearing design and are all designed to fit a 25mm shaft.

Pillow block bearing part numbering

Firstly, let’s look at the part numbering system used.

In the bearing industry these items are commonly known as :
UCP205
UCP305
UCPX05
The letters and numbers consist of the insert bearing style, the housing style and the series of bearing and housing.
UC tells us that the bearing is of an insert bearing type which extends on the inner race in both directions and that the bearing is designed to lock onto the shaft with a grub screw. This is a very popular and common bearing design for pillow block bearings.
P205
P305
PX05
These aspects tell us multiple things. Firstly, it tells us that the housings are pillow block bearing style so they effectively look like a hump backed bridge. We also know from this that they are manufactured from cast iron which again is standard for this series of bearing. The type of cast iron depends on the manufacturer but it would normally be HT200, HT250 or HT300 cast iron. The numbers
205
305
X05
tell us the series of insert bearing. So a 205 series bearing or UC205 bearing is used which is effectively based on the same dimensions as a 6205 bearing for the ID and OD and the 305 series bearing or UC305 bearing is based on the same dimensions as a 6305 bearing for the ID and OD.
Lastly, because these are metric bearings we can take the last two numbers of the part number and multiply it by 5 to get the inner diameter (or shaft size) of the bearing.

Some manufacturers have different ways of part numbering these bearings. Here are some of the more common variations

As you can see the majority of the bearings follow the same part numbering structure which is expected as they are all produced to the same JIS standard. The NTN bearings have a D1 at the end of them which just means that they have a relubrication feature on them. This is included on the other bearings as well but they don’t include a specific reference to it within their part numbering system. And then RHP have their own part numbering system entirely using NP25 for a standard duty bearing and MP25 for a heavy duty bearing.

25mm pillow block bearing dimensions

Next we will compare the catalogued dimensions of these bearings against each other. There are often subtle differences between manufacturers so when you’re looking for replacement pillow block bearings then it’s important just to make sure that the bearing you are purchasing will fit before buying. Normally this isn’t an issue but occasionally the bolt centres between manufacturers don’t always line up and can be a few mm out. In most applications this isn’t critical but on rare occasions it can be important.

UCP205 bearing dimension

As you can see the majority of dimensions are very similar across all of the manufacturers for the UCP205 bearing. This is to be expected as they are meant to be interchangeable but what if we look at the SKF UCP 205, SKF UCP 305 and SKF UCPX05 bearings ?

Here all of the bearings have the same shaft size but the remainder of the dimensions differ a lot between each of the products. This allows bearing designers selection to suit their application, a UCP205 is not going to be able to carry the same loads as either a UCPX05 or a UCP305. We can see this in the table below

As we develop the site further we will look to put the UCP205, UCP305 and UCPX05 bearings from each of the manufacturers on accelerated bench tests at various loads and speeds so that we can see how each perform under test conditions. We will also include slurry tests between bearing units with different sealing solutions so we can see how each performs under real life working conditions.

When purchasing your pillow block bearings please remember that the inner bearings and housings are interchangeable between manufacturers. If your bearing is damaged but your housing is still intact then you could save money by just purchasing the insert bearing and swapping them over rather than replacing the full bearing unit. If you have a RHP housing, you can order a SKF bearing to put inside it or vice versa, you don’t need to replace like for like although manufacturers will always recommend doing so.

We hope that you have found this information useful. If you think it would be beneficial for us to write on another bearing related topic then please contact us and we will add it to our workflow. We are keen to make sure that we become a knowledge resource for all things bearing related and bridge that gap of requiring industry experience to navigate the minefield that is bearings.

If you want to find out more information on the bearing manufacturers that we have covered today then please head over to our bearing manufacturers page for more information.