Hole punch guide

I needed to drill MANY holes on 1 inch metal bars, some at 1 inch center to center and some at 1/2 inch center to center. I designed this punch guide and use the little punch in the photo. A nail could be used instead. There is an overhang on one side in case you need to add more holes after welding (!?) to go over the 90° angle (you'll see if you make that error!).
Tolerances pretty tight (1.002 inch wide) because I buy good steel. You might want to print at 101%.