You can pull monster tension on stainless steel banding using a spin type tension.
The tool has a duck bill nose that is used to push against the stainless steel strapping seal. Screwing the handle pushes the seal further away from the gripper, pulling the banding tight. The spin type stainless strapping tensioner pulls more tension then any manual strapping tool. They are tough tools that hold up well.
We have seen people band large DC train motors with 304 series stainless steel banding, and use the spin type tool to compress it down. There are 3 versions of this tool, running up the 1 1/4″ stainless steel strapping.