This photo shows the floor screwed to its MDF support base and clamped in the mill. The tool I’m using here is a 6mm end mill which came in a set. As these tools are designed to mill steel, working on a polyurethan casting is hardly going to cause it much trouble. The mill’s table is shown at just about the end of its travel, this is why I had to stop half way through the job and shift the casting down so that I could mill the other end. Once this side was done, I unscrewed the casting and simply turned it around and milled along the other side.