Don't be surprised when parts warp during machining. On the contrary you should expect it. Warp is more of an issue when machining thin and hogged out parts. Thick heavy parts may not require the "special treatment" described in this chapter. Dealing with warp is actually quite simple and becomes second nature after a while. Regardless of how unstable a material is, by following a few of these simple suggestions you will be able to machine parts flat without much difficulty.

Warp is less an issue on lathe parts than on milled parts. Since the material being removed on a lathe part is the same or symmetrical around the axis of the part, the stress or release of stress from the machining is balanced out and the part has less tendency to warp.

Milled parts are more prone to warp. The amount of warpage depends on the internal stresses in the material and the degree to which the parts have thin sections and hogged out areas.

Raw stock that has been cold rolled or cold formed has more tendencies to warp during machining than hot rolled and stress relieved materials.

Whatever the material, you should assume the material will warp to some degree and plan accordingly. The following suggestions should help you make straight, flat parts regardless of how unstable the material is.

1. Skin cut all surfaces of a piece of material to begin.

   The first thing you should do is cut through the skin of the material on...