When installing transparent plastic enclosures held by bolts and self-locking nuts, how should the nuts be secured?

When securing self-locking nuts on transparent plastic enclosures, it is important to ensure that the nuts are not overly tightened, as this can lead to deformation or damage to the plastic. The correct approach is to tighten the nuts to a firm fit and then back them off one full turn. This method allows for adequate engagement of the self-locking mechanism while preventing excessive stress on the plastic material.

Self-locking nuts are designed to resist loosening due to vibration or thermal expansion, but if they are tightened too much, they may compress or crack the enclosure, ultimately compromising its integrity and functionality. By backing off one full turn after achieving a firm fit, you maintain a balance between security and protecting the structural integrity of the enclosure.

The other methods, such as tightening fully or leaving them loosely fitted, do not provide the same level of security and could either result in failure due to loosening or cause damage from excess pressure, respectively. Following the manufacturer's specifications is also wise, but in this case, backing off one full turn is a specific technique that accounts for the unique properties of the materials involved.