I dont have the attachments yet to clamp the chassis to my mill so I could do the sides. I can do the top and bottom of the chassis, but I do the sides by hand. Milling partially through the material is hard, I tried it on Kevin's chassis, but just decided to kill more weight by going through the chassis, he mainly runs stock and sometimes 19t so it should be fine for his needs, but I plan on mostly mod with mine, so I'll have to leave more material on the chassis...