Help - Schaublin 13 Variator Oil Seal

Ed P · Apr 23, 2018

My variable speed pulley is leaking oil. There is an oil seal marked STEFA 2240, does anyone know of a replacement? I'm not familiar with purchasing oil seals. The 2240 means it seals on a 22mm diameter shaft and the OD is 40mm but I've looked at various sites that sell seals and the configurations are different from the one I have. There are single lip, double lip etcetera... which one to buy... the one I have has just one very wide contact area, not really a "lip". And the rubber part fits in a C shaped channel.
Also, I would appreciate any help in getting O-rings that fit properly.

Thanks, ED

AlfaGTA · Apr 23, 2018

Need more information....Does it have a "garter" spring? what is the thickness as measured?
Is it a full rubber body or a steel case with a rubber lip...or is it rawhide?

I generally will use a double lip seal if the width permits....
Further if its an option i go with Viton for the lip material unless it is working against coolant or brake fluid...
Cheers Ross

hudson-ch · Apr 23, 2018

Hi,

I attach an extract of a drawing of the Schaublin 13. Checking the electronic catalogue of Stefa I was not
able to find a corresponding type.
Could you ask the US representative of Schaublin if he has a replacement type designation?

Good luck.
hudson

Bildschirmfoto 2018-04-23 um 21.03.07.jpg

rklopp · Apr 23, 2018

That looks to me like a plain vanilla lip seal with a garter spring. It does not appear to be sealing much of a volume or pressure. I would go through the online catalogs and match the od, id & width and call it a day.

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Martin P · Apr 24, 2018

I just took the variator apart on my Schaublin lathe and the leaking seals looked just like these.
They were regular oil seals, but not quite the most common dimension and in a rather unusual version with a metal outer ring and an additional metal front cover. I could have gotten a normal one for 4 Euro from EBay, but googled the correct ones, so now I ordered for 6 Euro the exactly "correct" ones. They are type "C". Many shops will have detailed explanations what all the different types mean.

Ed P · Apr 26, 2018

Martin P said:
I just took the variator apart on my Schaublin lathe and the leaking seals looked just like these.
They were regular oil seals, but not quite the most common dimension and in a rather unusual version with a metal outer ring and an additional metal front cover. I could have gotten a normal one for 4 Euro from EBay, but googled the correct ones, so now I ordered for 6 Euro the exactly "correct" ones. They are type "C". Many shops will have detailed explanations what all the different types mean.

I'd like to know what you googled because when I google "Stefan 2240 oil seal" I get nothing to do with seals. Schaublin, although still around, does not have anything to do with their milling machines and have no parts. Here is a picture of the seal, it's 40mm OD, 22mm ID the metal part is C shaped in cross section. Although it looks like it has a lip, it does not. The rubber part is square in cross section and fits into the channel of the C shaped metal. It's a solid piece of rubber, there is no spring.

Ed

AlfaGTA · Apr 26, 2018

Still waiting for someone to tell us the thickness of the seal....Is this too difficult for machinists????
Can't spec an appropriate replacement without knowing that bit of info.
Geeez
Cheers Ross

rklopp · Apr 26, 2018

Ed P said:
Although it looks like it has a lip, it does not. The rubber part is square in cross section and fits into the channel of the C shaped metal. It's a solid piece of rubber, there is no spring.

Ed

I don't see the need for a magic oil seal here. According to the diagram, practically any normal oil seal with the same OD x ID x W would do. The only reason I can think of to try to find the seal you cite is to restore your Picasso to absolutely original specs.

AlfaGTA · Apr 26, 2018

Not familiar with the mechanism here...but i suspect that this seal is made much like a plain old style "rawhide" seal that is really a wiper and does not have a formed
lip. Reason, and i am guessing, is that the seal must work on a shaft that is translating as well as rotating...here a modern lip with garter spring may not be the best design....

If that's the case, pretty sure you can find an equivalent seal...maybe not exact, but good enough to hold the oil in.

Cheers Ross

Luke Rickert · Apr 27, 2018

These are not pressurized oil systems like on the 135 variator, those seals were a pain to find but for this, as others have said, just get a high quality oil seal the correct size and you will be fine. I can check with my supplies over here but that would seem like overkill. So far anyway my 13's oil seals seem fine, I take it yours are dried out and dead. When was the machine made? If you can't find it easily in the US, you can probably order from simply bearings in the UK, shipping shouldn't be bad.
L

Ed P · Apr 27, 2018

AlfaGTA said:
Still waiting for someone to tell us the thickness of the seal....Is this too difficult for machinists????
Can't spec an appropriate replacement without knowing that bit of info.
Geeez
Cheers Ross

Sorry, the width is 4.75mm. I've looked through online catalogs and I can't find a seal that looks like this one. Does it matter? Can I just buy any seal with the same OD and ID? The ones I've seen do not have a steel housing like this one. Does it matter? I can find one that's all rubber with a spring under the lip, will that do? Sorry for the basic questions but I have never purchased seals before and am overwhelmed by the multitude of different configurations.

Ed

rklopp · Apr 27, 2018

More than one person, including me, has said it does not matter. Sue us if we're wrong. Look at the place where the seal goes. What is the widest seal that will fit? Buy that one. See if you can find one in the catalog that is meant for axial motion, like for a hydraulic cylinder rod. I don't think it matters whether the seal's outer casing in steel or rubber coated, as many are. It matters more that you don't nick the seal lip during assembly, than the exact details of the seal lip design.

Martin P · Apr 27, 2018

If you don't use a Stefan seal you may get split ends.

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