This study presents briefly the application of fractal geometry in internal threads surface characterization to reveal defect fine structures of the internal thread geometry caused by the manufacturing process. The surface texture characteristics of ten internal thread samples M12 × 1.75 of low carbon steel Ç1020, manufactured by cutting tap and rolling tap were analyzed and discussed through comparative analyses of the experimental data. The surface characteristics of samples were analyzed using scanning electron microscopy (SEM) and were found that surface texture characteristics (Str – surface anisotropy ratio and D – fractal dimension) are different for the thread specimens.