49-Pc Thread Chaser Set, Metric and SAE Taps Dies Files

A 49-piece thread chaser set built to clean up threads you already have, not cut new ones. It carries 22 taps, 24 dies, and 3 thread files covering SAE 1/4 in. through 9/16 in. in both UNC and UNF, plus the metric sizes that show up all over a driveline: M6, M8, M10, M11, M12, and M14. A chaser follows the existing thread form and pushes out rust, thread locker, sealer, and raised burrs. A cutting tap removes metal and leaves you with a looser hole, which is exactly what you do not want in an aluminum case.

On transmission work this is the tool you reach for before the pan goes back on. Pan rail holes on a 4L60E, 4L80E, 700R4, or a Ford 4R70W collect old RTV and pull threads out of the case when a bolt is run in dirty. Run the correct chaser down each hole, blow it out, and the bolts seat square and hold torque instead of spinning at 90 in-lb. Same story on bellhousing bolt holes, cooler line fittings, crossmember bolts, and the extension housing bolts that get chased with a wire wheel and never really get clean.

The dies handle the other half of the job: bolts and studs that came out with damaged leads. Chase the stud, chase the hole, and a bolt that fought you on removal threads in by hand on reassembly. Taps and dies are hex-bodied so a standard wrench or socket drives them, which matters when you are working a bolt hole up inside a bellhousing with no room for a T-handle. Steel construction with a black oxide and zinc finish, and the whole set stores in a molded case so sizes stay sorted on the bench.