Threaded fittings on their internal (female) or outer (male) surfaces have screw threads (built-in grooves) intended to accept connections with corresponding threads. Threads are called straight threads that provide an easy connection but no guaranteed seal.
Hydraulic fittings connect conductors such as hoses, pipes and tubes in a hydraulic system. Most Hydraulic fittings have a male and female component that join to form a connection.
O-ring failure can be traced back to design, installation, production quality and material choice. Choosing the proper materials, size, compression and surface finish will make a big different in machine performance and longevity.