Hi, We have done cutting shapes to 140mm deep. I had some 170mm x 16mm spirals made for it, which worked OK, but found that there was a lot of burning above the flute (and sharpening made it impossible). The best was to use replacement tip straight cutters where possible, as they keep diameter, and the cut is wider than the body and the shank. I found it best to bandsaw to rough shape and cut in 2mm increments from the outside in, as this allowed using more of the cut length (eg 30mm), and overcame the lack of safe Z isssues, as it could (with care) be programmed with the cutter always below the top surface of the work. It was fine provided you kept the collet at least 2mm above the work. You will definitely need a spindle for it. Have fun, but tread carefully. R.