Pitch
Lead
Thread- & helix angle
Crest- & root radius
Major & minor diameter
Effective diameter
Flank clearance angle
Tilt angle
Right & left hand thread
The main menu
The sub menu
The pages
The test
Right hand screws: Screws that move forward when turned to the right (clockwise).
Left hand screws: Screws that move forward when turned to the left (anti clockwise).
Generally most screws are right hand threads however left hand threads do exist.