All 8 of the seat ribs have to have a tooling hole enlarged to 5/8” for a snap bushing. I guess for wires later. I normally clamp the piece on the bench press when using the step drill. But, talking to my brother Steve, he say’s “Just hold it down and go for it”. Well, works for me. I have a 1” hole in my bench under the part for the step drill to sink into. I debured the hole with the yellow handled tool you see in image 2.
