This is a table of sizes and markings for 3/8 and 5/8 buckles in our example. I then attached the chart to the fixture so it is always available.
Step 7: Drill ‘Dimble’
On the opposite end of the base, drill a ½” ‘dimple’ near the inside edge of the base. During storage and transport the dimple will provide a hole for the nut of the 5mm screw to sit in (so that the slotted bar will sit flush to the base).