I am wondering if anyone can point me in the direction of some guidelines for lightening holes.
I am restoring a car and I'm building a perimeter frame out of 3" x 4" x .120" astm 500 C steel tubing. I would like to put lightening holes in the4" side. I was thinking 2" holes on 4" centers. I would like to go larger if possible, without totally removing the strength of the tube.
Also, is it possible to purchase a set of dies to flair the holes ? I am guessing I would have to use something like a shop floor press. to form the flare.
Thanks in advance for any help.