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:
Spacer, ¾" OD x 7/16" ID x ⅝" Long
Product Details
Brand: Welder Series
MPN: 21253-A
Country/Region of Manufacture: Canada
Diameter: 3/4"
Length: 5/8"
Hole size: 7/16"
Used in our Granada Mustang II brake kit.