[Justin M.]

We have a mill, but decided to cut out square portions of our chassis with a jigsaw to keep the weight down. Milling would take too much time due to the length of the sections that need to be removed, and we only have one somewhat small and cramped mill/lathe. Ideally, we have 3 or 4 jigsaws so more than one person can work on cutting the pieces out at a time.

The way I cut out a square section in the middle of a sheet of metal is to drill a 3/8" hole on the corner points of the square, so you can fit the jigsaw blade in there to make the cut.