I need to replace a missing valve handle for a 4" gate valve; the valve drains my lake and is not removable. The stem has a tapered square shaft about 9/16" tapering to about 1/2". I had been using a 8-point socket for a handle but it slipped and took some corners off. A 9/16 4-point socket might work but I can't find one. A regular bolt on handle would probably be best, where do I find them? The valve is very old and partially buried in the mud so I don't know who made it. Are there any standard valve handles that would fit, or any adjustable 4-point sockets availiable?
Any helpful suggestions appreciated