The SL31C-12 stud is a PMA aircraft engine threaded stud used in Continental-compatible piston engine assemblies. It is a double-ended steel stud with 5/16-18 UNC coarse threads, designed to be installed into engine cases or engine components to provide a durable, reusable threaded mounting point for nuts, brackets, or accessories.

It is used in locations where repeated maintenance or disassembly would otherwise wear internal threads in the engine case.

Key features include:

PMA aircraft engine stud fastener
Diameter: 5/16 inch
Thread: 5/16-18 UNC coarse thread
Precision-machined steel construction
Double-ended threaded design
Installed into engine case or structural components
Provides reusable mounting point for engine assemblies
Prevents wear of internal case threads
Designed for vibration and cyclic engine loads
Compatible with Continental piston engine configurations (IPC-dependent use)
Used in engine assembly, accessory mounting, and overhaul procedures