ARP's Thread Cleaning Chasers are designed with correct thread pitch and diameter to clean dirty blind or thru holes. These taps come in five USS sizes: 1/4", 5/16", 3/8", 7/16" and 1/2", as well as metric. They are a handy addition to the tool box of any serious engine builder and an essential aid to preparing any block for final assembly. Sold individually.
Note: These are strictly cleaning taps and are NOT designed to cut thread.