Bolt in cage?

Back in the late 1970's we needed a five point bar to run 12.50's at my local track. My street car Duster had gone 11.80's so I put in a plated bolt in four point cage from Summit and a buddy of mine welded a pinned driverside bar to ease getting in and out. I remember this like it was yesterday the issues I had drilling holes for the plates. My Dad was an Electrician so he had a VERY powerful Milwaukee 1/2 inch drill. Well being young and dumb I plugged drill into the trouble light. Drilling at an angle because of the rollbar the bit grabbed when the bit entered the plate under the car. As the drill grabbed it spun and I hit the button to hold the trigger in. Before I knew it I had a badly sprained wrist and shattered light bulb all through my Duster form the cord wrapping around the drill. Lesson learned, THE HARD WAY.