When we ran a full service chassis fab/turn-key hot rod shop a number of years ago, it was always useful to have threaded things around to weld into the frame for some kind of mount, etc.
Here’s a list of all our threaded things for your reference:
Exhaust
Grommets, hangers, and flanges, most sizes available in stainless and mild steel. If you have a need that's not met by our standard hangers or flanges, please contact us- we do custom pieces regularly.