exhaust header nut help

[Fazer Jake]

I've not seen such nuts on sale, but when I sheared one of the studs on my Fazer, I cobbled something similar together by welding two nuts together and filing. Alternatively and perhaps easier, short length of steel rod could be tapped with a 6mm thread and filed.

something like this i was thinking



so it just fits through the header as a temp measure

need help on size/where to loook tho