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:
Aluminum Washer; 1-3/8" OD, 5/8" ID
Product Details
Brand: Welder Series
MPN: L7-1077
Country/Region of Manufacture: Canada
Thickness: 3/8"
Diameter: 1-3/8"
Hole size: 5/8"