Its all free hand with a drill for me. I don't have a drill press.....could you catch in one of those pics where I am using the metal bracket as a guide (drilling the first hole, inserting a screw to hold it in place,,,drill the next, insert a screw and so on. Also, those clamps do not need to be the most precise thing in the world...so a slightly larger bit than the bolt and you can do it free hand with no issues. I built all my forms like that.