Grease guns are primarily used for inserting grease into what?

Grease guns are primarily used to deliver grease into Zerk fittings on machine tools. Zerk fittings, also known as grease fittings, are specially designed ports that allow for the maintenance of machinery by facilitating the easy application of lubricant. The function of a grease gun is to provide a controlled means of injecting grease into these fittings, ensuring that critical moving parts are lubricated effectively to reduce friction and prevent wear and tear.

Professionals often utilize grease guns to maintain equipment, extending the lifespan of machinery and minimizing the risk of failure due to inadequate lubrication. This process is essential in various applications, particularly in manufacturing and automotive industries, where machinery operates under significant stress and load.

In contrast, the other options do not accurately represent the primary use of grease guns. Hydraulic lines and pneumatic systems require specific types of lubricants or fluids other than grease, while electrical components usually demand non-conductive lubricants and careful maintenance to prevent shorts and other electrical issues. Consequently, the focus on Zerk fittings highlights the grease gun's role in ensuring optimal performance and longevity of mechanical systems through proper lubrication.