I've got a standard manual grease gun with a short pipe (~1") and want to replace it with longer one. I've tried to remove it, but it is stuck. I decided to either get 2 small nuts and twist them on against one another then use a wrench on the inner one to unscrew pipe or get a connecting nut to just add the extension. I can't determine the thread size on the pipe. Closest I've come to getting a match is an M10-1.0, but even that binds up after about 3 turns. Anyone know what the thread size is on standard grease gun fittings?