Bearing markings

[daxliniere]

Hey gang,
I recently got an Arboga U2508 mill (Yes, the EM825 will be up for sale soon) and there's a bit of noise coming from the front of the gearbox. (definitely front, not generalised) Nothing terrible, but a bit rattly, so I opened it up to see. There are 3 shafts; drive (motor), intermediate and output (spindle). The grease in the bearings of the latter two are the original yellow colour, but the output shaft's bearings are greyish. To my line of thinking, this is probably microscopic metal particles indicating wear. This matches up with the audible indication.

The bearings are FAG brand 6203, open-type bearings, but there is another marking on them that appears to be V.U
The AI oracles of ChatGPT and Gemini suggest it might be a tolerance marking... or just an internal company code. Can anyone confirm what V.U means, please?


All the best,
Dax.

 

[Barking Mat]

Doesn't seem to correspond to any of their codes.

 

[m_c]

This setup?


As they're not the actual spindle bearings, I can't see them being anything special.
A quick google, suggests a V on it's own indicates a full compliment bearing with no cage, which should be easily visible on an open bearing ( https://www.ahrinternational.com/FAG_nomenclature.shtml )

As you mention, it could be some kind of specific variation, or just a manufacturers mark.

Personally, I'd take the bearing out, and provided everything else looks like a standard bearing, I'd just fit some standard bearings.

 

[daxliniere]

Hey @m_c, yes, that's the gearbox. She's a beauty. Everything is so nicely machined and thankfully all of the phenolic gears in mine are in great condition.
Thanks for the link to FAG's nomenclature. I know that mine are an open type of bearing. I'm almost certain I saw a retainer ring, but I wouldn't bet my life on it.
I looked up photos of full complement, retainerless bearings and am pretty sure I would have noticed if it was just a bunch o' balls, as I don't think I'd ever seen that in a bearing before.

I'll wait for a couple more replies, but I think I will do as you suggested a just grab a pair of standard 6203s.
Having said that, bearings are so cheap these days, I don't mind shelling out a couple quid extra if there's a better bearing for this application.

 

[Seadog]

Can anyone confirm what V.U means, please?

Surely you've come across V.U. in your day job?
It relates to the amount of noise the bearing makes...

 

[tigdlo]

Where is the V.U marked? I've always seen the specifications engraved together so if it's marked away from the size then it is likely unrelated to the specification. Could you post a photo?

For example the bearing below, the symbol that looks like a like B or 13 is unrelated to the specification.

 

[daxliniere]

Surely you've come across V.U. in your day job?
It relates to the amount of noise the bearing makes...

Baaahahaha!! Very good.

(For the rest of you: I'm an audio engineer. )

 

[tigdlo]

Having said that, bearings are so cheap these days, I don't mind shelling out a couple quid extra if there's a better bearing for this application.

I forget to add, the extra couple of quid would be best spent getting a decent brand from a well established reputable supplier rather than a decent brand from the cheapest seller on ebay or amazon as there are many counterfeits about.

 

[daxliniere]

@tigdlo IIRC, it's stamped roughly where the PORTUGAL is stamped on your example.

 

[Pete.]

For ordinary shaft bearings in that box I'd just fit a standard 6203 except I'd fit rubber shield bearings and I'd change them all just because.

If you do fit open bearings then don't use a plastic hammer to knock them in like so many people do. You will likely end up with tiny bits of plastic in the bearing from the hammer face.