3/4" to 1/2" stainless steel butt-weld pipe fitting (McMaster-Carr p/n 45605K711 Link
1" stainless socket weld low pressure coupling (McMaster-Carr p/n 4335T64 Link
I solder the washers on the fittings
and use a grade 8 fine thread bolt and nut.
The bolt needs to be lubricated with an aluminum paste or it will only be good for about 4-5 holes before the threads start to give out.
One other item I added was a bearing to the swage assembly.
Fully assembled swaging tool:
is a YouTube video
The video shows the butt-weld fitting being pressed back out. One whack with a hammer is far faster.