Chapter 9 Profile Tolerances 325 Profile of a Surface All Around or All Over Surface profile can also be applied to completely blanket objects that have a constant uniform cross section by placing the all around symbol on the leader line. When this is done, surfaces all around the object outline must lie between two parallel boundaries equal in width to the given geometric tolerance. The tolerance zone should also be perpendicular to a datum plane. Refer to Example 9-11. The all over symbol, shown in Example 9-11, is used when it is necessary for the profile tolerance zone to be all over the entire part. The Drawing The Meaning (All around application. All over covers the entire part.) 90° Datum plane A 0.4 wide profile tolerance zone May not exceed R0.2 All around symbol All over symbol or This dimension has a tolerance when the all around symbol is used, or the dimension is basic when the all over symbol is used Example 9-11. Using a profi le of a surface tolerance all around or all over.