el Diablo Guapo
Member
McMaster Carr sells this:
https://www.mcmaster.com/#5896k2/=18yiosf
https://www.mcmaster.com/#roller-chain-tensioners/=18yiora
They are plastic, but i used chainrings off wheels and cranks for mine.
Seems to be working, but I also keep imagining a throwing star to the gunuchskis...