Wire Size for Piano Hinges on RV-7 Seat

Quick questions...
Will someone please tell me the diameter of the piano hinge wire for the seats on an RV7, and a good place to buy it?

Thanks

.089 although a few thousands smaller is ok available at ACS or you local hobby shop

DWG 30 hinge is part number F-637D and E. From the parts list, F-637D and E are AN257-P3.

AN257 (or now MS20257) spec (available at Genuine Aircraft Hardware...buy the little blue book they sell! It's a great reference guide to all things AN/MS) shows P3 as

hole diameter .093, pin diameter .090 (for aluminum hinge).

http://gen-aircraft-hardware.com/images/pdf/ms20257.pdf