Drill America 5/16-18 UNC HSS Bottoming Tap
 
Used to make new threads or re-thread damaged and or jammed threads
Hand Taps are the most versatile taps for hand use
They are popular for use in general machine tapping
Appropriate for tapping the vast majority of materials in through or blind holed conditions
Hand Taps come in three styles Taper, Plug or Bottoming