Snap-on Incorporated
Internal thread chase

Abstract:

Disclosed is a thread chase or tap capable of being inserted past damaged threads of a female threaded coupling and then rotated back to repair the damaged threads. The thread chase can be selectively expanded to engage chase blocks having cutting teeth against threads. Thereafter, a user can rotate the thread chase in a direction sufficient to cause the thread chase to move axially out of the female threaded coupling. Upon doing so, the chase blocks can be pushed outwardly and engage undamaged threads, and rotated so as to move upward and repair damaged threads.