A 4 1/2" angle grinder with a thin wheel is probably the easiest BUT MOST DANGEROUS way to make the initial cuts. A drill or hole saw is a slightly better choice since it leaves a rounded corner, reducing the chance of a stress crack or tear. But an air hammer with a slitting chisel is safest & quickest.
If using a wheel, remember that it sprays red-hot steel either up into the truck, or down onto the fuel tank. Since this truck had no camper shell or interior, I let it fly up & wore safety goggles & ear plugs.
![05start.jpg A 4 1/2" angle grinder with a thin wheel is probably the easiest BUT MOST DANGEROUS way to make the initial cuts. A drill or hole saw is a slightly better choice since it leaves a rounded corner, reducing the chance of a stress crack or tear. But an air hammer with a slitting chisel is safest & quickest.
[url=https://www.supermotors.net/vehicles/registry/media/1158168_1][img]https://www.supermotors.net/getfile/1158168/thumbnail/20200318_154121.jpg[/img][/url]
If using a wheel, remember that it sprays red-hot steel either up into the truck, or down onto the fuel tank. Since this truck had no camper shell or interior, I let it fly up & wore safety goggles & ear plugs.](https://www.supermotors.net/getfile/309586/fullsize/05start.jpg)