Review on O'SKOOL Self-Centering Dowel Jig Kit with Drilling Guide Bushings - Wood Doweling Jig Puncher Locator for Wide Capacity Joints Tool by Michael Briggs

I used this to center holes in 2.5" steel tubing. The conductor could not prevent the drill from tipping over in the steel. With no flaws of the luminary, it was intended for a slight hardness, like wood. Then I could see the hole. I finished the job using a drill press to keep the 1/4 wall material straight. Also pay special attention to the number of drill sleeves of each size. Depending on your application, you can drill just one hole and then move the sleeve for the second hole. The quality was much better than some other lights on the market and the gauges were clearly visible. I would turn to a woodworking friend, but not a machinist.