Connecting old high tank toilet

[dsap1]

I bought a new brass 7/8 toilet filler to mount through bottom of high tank on wall. I want to run 1/2 copper pipe to the 7/8 straight thread connector on filler...How can I do this? What parts are needed? Doesn't seem to be a common part from Lowe's. I could also change the filler if I had to. I just want all copper showing no plastic.

 

[IFIXH20]

There is a good chance 1/2'' copper piping or a 1/2'' copper coupling could be slodered inside the brass fill valve where the supply line attaches to the fill valve. I have never done this but just thinking about it. You can always run a 3/8'' copper line to the fill valve as well using the rubber gasket and the brass nut & washer to attach the 3/8'' line to the fill valve.