(feeler surfaces) ground. Sometimes, if convenient, the feeler surfaces may be machined in a part of the fixture. These should be clearly marked so that the operator is certain as to which are the feeler surfaces. In its correct setting, the cutter should clear the feeler surfaces by at least 0.08 cm to avoid any damage to the block when the machine table is moved back to unload the fixture. The thickness of the feeler gauge to be used should be stamped on the fixture base near the setting block.