Fred Lustig in Nevada and Ken Ruth at Photography on Bald Mountain are the people I've used in the past. Fred is a whiz at Graflex related stuff and bought up all of Graflex's inventory when they closed shop a number of years back. Ken Ruth has repaired insanely obscure fp shutters for me and has repaired Speed Graphic shutters as well and is meticulous and slow and sort of expensive, but he will do the job right. Both guys are highly recommended.