Fluval FX4/FX5/FX6 handwheel locking nut

thingiverse

This redesign significantly enhances the reliability of the fluval locking handwheel for the FX6. Notably, it features additional reinforcement to prevent breakage under stress. The designers have carefully optimized the tolerance on the center hole where the nut is seated, ensuring a snug fit. To achieve this, printing with ABS requires scaling up by 3% to compensate for shrinkage during cooling.