T-

Yes, I've had an account there for 10 years. Mcmaster is an absolute must. No frustrating trips to 5 different hardware stores every weekend only to come home either empty handed or with some stuff you settled for. Just order and exactly what you are looking for and it magically appears on your doorstep the very next day.

But for cork, I found this place the other day and think it might be just about right - http://www.thefeltstore.com/ - no 5/8" but 3/8, 1/2, 3/4 and 1"