Fastener grip length selector

A fastener grip length selector, comprising:

• an axis;
• a cylindrical housing extending along said axis and including a first section and a second section;
• and
• a gauge, including:
• a clamping shaft, wherein said clamping shaft has a cylindrical shape and extends along said axis, and wherein said clamping shaft is in a fixed connection with said second section of said housing;
• a spindle, wherein said spindle is inserted in said clamping shaft, wherein said spindle extends along said axis and reaches into said first section of said housing, and wherein said spindle is movable within said clamping shaft along said axis;
• a spring, wherein said spring is in contact with said spindle, and wherein said spring is compressed with said spindle;
• and
• a digital display, wherein said digital display displays a length corresponding to the movement of said spindle along said axis;
• wherein said gauge translates the movement of said spindle into a length displayed in said digital display.

A calibration system, comprising:

• a reference standard;
• wherein said reference standard includes:
• a structure including a top surface and a bottom surface, wherein said structure has a known thickness measured from said top surface to said bottom surface;
• and
• a fastener hole machined into said structure, wherein said fastener hole extends from said top surface to said bottom surface of said structure;
• a temporary fastener installed in said fastener hole, wherein said temporary fastener includes a top;
• and
• a fastener grip length selector placed over said temporary fastener, wherein said fastener grip length selector contacts said temporary fastener at said top, and wherein said fastener grip length selector contacts said top surface of said structure;
• wherein said fastener grip length selector indicates a length.

A system for measuring an assembly thickness in a clamped-up condition, comprising:

• an assembly including a plurality of panels, said assembly having an outer mold line and an inner mold line;
• a fastener hole machined into said assembly;
• a temporary fastener installed in said fastener hole, said temporary fastener including a top and providing a clamp-up force to said assembly holding said panels together;
• and
• a fastener grip length selector including a housing, and a gauge including a spindle, said fastener grip length selector being placed over said installed temporary fastener, wherein said housing is in contact with said outer mold line of said assembly, wherein said spindle is in contact with said top of said temporary fastener, and wherein said gauge translates the movement of said spindle into a length.

A system for measuring the thickness of an aircraft airframe assembly in clamped-up condition, comprising:

• an aircraft airframe assembly including an outer mold line skin, a sealer, and a substructure, said assembly having an outer mold line, an inner mold line, and a thickness;
• a fastener hole machined into said aircraft airframe assembly, wherein said fastener hole is a blind hole not accessible from said inner mold line;
• a temporary fastener installed in said fastener hole, said temporary fastener including a top and providing a clamp-up force to said aircraft airframe assembly holding said outer mold line skin, said sealer, and said substructure together;
• a fastener grip length selector, comprising:
• a gauge including a display, a spindle, and a spring in connection with said spindle, and a housing supporting said gauge;
• and
• a reference standard having a known thickness and including a fastener hole, wherein said reference standard calibrates said fastener grip length selector;
• wherein said fastener grip length selector is placed over said installed temporary fastener, wherein said housing of said fastener grip length selector is in contact with said outer mold line of said assembly, wherein said spindle is in contact with said top of said temporary fastener, and wherein said spindle compresses said spring;
• and
• wherein said thickness of said aircraft airframe assembly is deduced from the gauge reading displayed in said display.

A method for precisely measuring a thickness of an assembly in clamped-up condition, comprising the steps of:

• calibrating a fastener grip length selector using a reference standard and a temporary fastener;
• installing said temporary fastener in an assembly having a thickness;
• placing said calibrated fastener grip length selector over said installed temporary fastener;
• making contact between said fastener grip length selector, said temporary fastener, and said assembly;
• reading a length displayed on said fastener grip length selector;
• and
• deducing said thickness of said assembly from said reading.