87-Piece Tap and Die Set, SAE and Metric Threading Kit

An 87-piece tap and die set covering both SAE and metric, coarse and fine. 78 of the 87 pieces are the taps and dies themselves, running 4-40 through 5/8-18 on the inch side and M3 through M16 on the metric side, so one case handles case bolt holes, pan bolt holes, cooler line fittings, and the odd bellhousing stud without hunting for a loose tap.

On the bench this is mostly a cleanup tool. Aluminum transmission cases pull threads easily -- pan rail holes get overtorqued, valve body bolt holes fill with old sealant and thread locker, and a case that has been apart a few times will have at least one hole that fights the bolt going back in. Running the correct tap down the hole clears the debris and straightens the first few threads, which is the difference between a bolt that torques to spec and one that reads correct on the wrench while actually sitting on a wad of packed sealant. The dies do the same job on studs and on the threaded ends of cooler line fittings that got dinged during removal.

The taps and dies are GCr15 bearing steel with a titanium plating, and they cut carbon steel, cast iron, aluminum, brass, copper, and stainless. Five adjustable wrenches are included -- the dies lock into the wrench rather than floating, which keeps the die square to the work so you are not starting a crooked thread. Also in the case: two thread pitch gauges for identifying what you are looking at before you pick a tap, a 1/8 inch screwdriver, and a 5 inch center punch for marking a hole before drilling.

Note that this is a threading and rethreading set, not an insert kit. If a hole is stripped past the point where a tap will bite, you need a thread insert kit instead -- this set cuts and cleans threads, it does not replace missing material.