Bolt Nut MT and PT Exam Flaw Specimen (Metric Version) Carbon Steel Bolt Nut MT PT Exam Flaw Specimen Bolt Nut Magnetic Particle and Liquid Penetrant Exam Flawed Specimens. Geometry: 32mm OD x 150mm long. Flaws: 3, randomly placed Standard Tolerance: +/-4mm. Documentation: NDT Verification Reports, C of C, CAD Drawings and Test Sheets. Material: Carbon Steel. Customized Calibration Test Block and Flaw Specimen also available.