Use a hydraulic press to gradually and smoothly increase pressure until the broach is forced through.
Making a sqaure hole sheet metal.
If the hole is a lot bigger then your biggest drill bit then drilling holes round the edge of the square and then connecting them with a saw is the best way for you.
Blacksmithing for beginners cutting a square hole in sheet metal.
How to make a square hole without using special tools.
This will create dimples in the sheet.
Put your ink to the use and mark the hole center.
Making a square hole in a plough blade.
Ensure you fix the metal sheet down when you drill do not hold in you hand.
Now it s time to use that center punch.
How to use chisels instead of files to cut a share hole for carriage bolts.
Go slow and drill a smaller hole first ti guide the bigger rill bit.
Insert the broach and ensure it lines up at 90 degrees from the work peice or the hole will be crooked.
Drill a hole in the metal close to but smaller than the finished hole size.