Crab shells, often considered wastes, have the potential to be a valuable source of chitin nanofibrils (ChNFs) for various applications. This study introduces a novel, cost-effective method where NaOH treatment and concrete mechanical vibrator (CMV) produce high-quality ChNFs while maintaining their native properties, such as crystalline structure and higher degree of acetylation. This method, which is the first of its kind, addresses the challenge of developing a scalable approach to ChNF preparation. The crab shells underwent pretreatment with 20% NaOH four times over 2 weeks. Fourier transform infrared spectroscope (FTIR) confirmed preserving the α-chitin intrinsic structure after chemical treatment and mechanical disintegration. The resulting individual ChNFs displayed 82% crystallinity and 86% degree of acetylation, indicating the preservation of their physical properties to a large extent. The ChNFs had a diameter ranging between 10 and 23 nm, as observed under a scanning electron microscope (SEM). Rapid removal of water from the ChNF colloidal suspension using a vacuum pump allowed for forming a ChNF film by drying the resulting wet cake under pressure in an oven. The film exhibited impressive mechanical properties with a tensile strength of 149.9 MPa, Young's modulus of 8.4 GPa, and tensile strain of up to 7.1%. The combination of NaOH and the mechanical vibrator for mechanical disintegration presents an innovative and advantageous approach for scaling up production, especially considering the recyclability of NaOH as an industrial chemical.