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:
Sway Bar Mount
Product Details
Brand: Welder Series
Thickness: 3/16"
Hole size: 5/8"
Formed, with a radius to fit on a 1-3/8" tube. 2-1/4" x 2-1/4" with a 5/8" hole.