Anyone know what I can use for an air seal on a small shaft, with rotary-only motion? Say about a 1/8" dia shaft. OD of the seal I'm flexible on.

I am not sure how an O-ring will hold up to rotary motion (as I've always felt they were for static operation), but I could be wrong there. Will an oil seal work for air? I've even thought I could use a double-sealed or double-shielded ball bearing. I did find "cup seals" at McMaster but they don't come in smaller sizes.

I don't need a 100% seal, because I'll have air flowing through it.

Thoughts appreciated.

Cheers,
-Neil.