The divider is one of the handiest tools for bench work fabricating.
A 5" and 3" divider will do a lot for you.
Set it to 3/8" and mark a spot to center punch.
Setting the distance between hole centers, 3". Using a 5" divider for this action.
Set one end of the divider into the punch spot to mark the second hole location.
Punch the other hole center and use the spots to layout the shape.
Drill, 1/4" and 5/16" holes.
Get busy with some filing.