This might be well known to the more experienced machinists but it is a useful idea. MDO (medium density overlay) and MDF, basically plywood or particle board covered with a plasticized paper material, is dimensionally very accurate in thickness and it's sides are usually parallel to an .001" or so and has an excellent finish.
You can clamp this material to a face plate or milling table and mount your work piece onto it and if you have to cut through the part the board takes the damage, just throw it away when it is to chewed up to use anymore.
You can clamp this material to a face plate or milling table and mount your work piece onto it and if you have to cut through the part the board takes the damage, just throw it away when it is to chewed up to use anymore.