SANDS138 RTP SLOT Materials that can be milled range from aluminum to stainless steel and almost everything in between. Nearly all types of metal can be turned, although more time & specialist cutting tools are needed for harder workpieces. In the metal trades area, marking out consists of transferring the engineer's plan to the workpiece in preparation for the next step, machining or manufacture. A hardened cutting tool is held at the desired height (usually the middle of the workpiece) by the toolpost. Journal of Materials Processing Technology.|The Do's and Don'ts Of Slot Tech Forum