Thread Cleaning Taps by ARP

Dirty threads can cause a variety of problems, from incorrect torque preload to ineffective thread locking compound. In extreme cases, damaged threads or foreign matter in a blind hole can prevent a bolt from installing fully. If this happens in a casting, tightening the obstructed fastener can crack the hole, resulting in total part failure. (Yes, that was a very expensive lesson... )

Trying to clean and dress threads with a conventional thread cutting tap can cause more damage to the threads: Removing material and weakening the threads (best case) or even cutting entirely new threads (worst case).

Thread cleaning (chasing) taps are the proper way to clean and dress female threads. Instead of cutting new threads, these special tools are designed to remove foreign matter and to straighten the existing threads if necessary. They are a must for any rebuilder's tool box.

Thread cleaning taps also make very handy thread pitch gauges! Just hold your mystery bolt side-by-side against one of these taps. If the threads mesh, the thread pitch matches.