What should be applied to the front swivel screw threads to ensure the swivel screw nut remains tight?

Applying Loctite to the front swivel screw threads is effective because it is a type of thread-locking adhesive designed specifically to prevent screws and nuts from loosening due to vibration or movement. This adhesive creates a strong bond that holds the screw in place, ensuring the swivel screw nut remains tight over time and under operational conditions.

In contrast, varnish, wood glue, and screw lubricant do not fulfill the same purpose. Varnish serves as a protective finish for wood surfaces, which does not affect the stability of threaded connections. Wood glue is meant for bonding pieces of wood together rather than securing screws. Screw lubricant, while it can help with the ease of turning screws and reduce friction, does not provide the strong locking effect that Loctite does. Therefore, using Loctite is the most appropriate solution for maintaining the tightness of the swivel screw nut.