Lots of posts about this - but of course, it depends on what / where you are flying. AFAIK, if one were flying exactly the same route (ORD-NRT-BKK) in Y, as oneworld sapphire or emerald / AA Platinum or EXP, one would have lounge access at ORD outbound, and NRT on the return (not NRT outbound or BKK anytime,) given that the flights described between NRT and BKK are NOT on oneworld metal.

If your questions concern other flights or locations, you would need to be specific for anyone to comment on lounge access information.