setscrew
/ˈsɛtˌskruː/
noun
- A small screw used to hold a part, such as a gear or pulley, tightly onto a shaft or axle.
- The mechanic tightened the setscrew to keep the gear from slipping.
- The setscrew came loose, causing the wheel to wobble.
- You need a special wrench to adjust the setscrew on this machine.