There’s nothing new about the concept of taps and dies. Such tools have been in use since sometime early in the 18th century when blacksmiths began making threaded fasteners out of metal instead of wood. But there have been countless improvements and innovations in tap-and-die design over the years, and some of the latest can be found in the Performance Threading System (PTS) from Irwin Tools (www.irwin.com). This collection consists of separate tap, die and drive-tool sets, each packaged in a locking plastic case with a clear plastic top.
Aside from their high-quality construction and materials, what makes the Irwin taps and dies different is their self-aligning feature. With conventional taps, which have either full or tapered cutting flutes that begin right at their very starting end, the tap sometimes resists maintaining proper alignment with the hole as the cutting process is begun. But with these Irwins, the first 15 percent or so of each tap has a smaller, non-cutting diameter that’s a precise fit into the correct-size hole for the tap size; this allows the tap to be perfectly aligned before any cutting begins. You just place the tap into the opening and begin cutting, assured that the threads will be perfectly straight from the start.
A similar design allows the Irwin dies also to have perfect starting alignment. The first section of the cutting area has no flutes and is sized to fit perfectly over the bolt or rod being threaded; thus, much like with the taps, you slip the die over the end of the bolt/rod and begin turning, with no worry about the first couple of threads being compromised.
Irwin’s PTS tap design does, however, prevent holes from being tapped all the way to the bottom. This requires what are called “bottoming” taps that have full flutes from start to finish. With the Irwin dies, though, you can just flip the die 180 degrees and finish the cut all the way to the base of the bolt or stud if so desired.
Plus, Irwin’s drive-tool set contains an innovative “drive stock” (the traditional name for the handle used to turn the taps and dies). Unlike other drive stocks, most of which use a small set screw to hold a die in place, the Irwin has a nifty locking wheel. You just drop a die into the hex opening on the back side of the handle and give the wheel a 1∕6 turn to the right, which locks the die in place and holds it securely.
In addition, the set includes two adjustable tap-socket holders (one for the smaller taps, another for the larger) that also drop into the drive stock and lock in place with the wheel. What’s more, if there’s not room to swing the 9½-inch-wide drive stock, the set comes with a 4½-inch, removable T-handle, along with both SAE and metric thread gauges.
High-quality tools are never cheap, and neither are these Irwin sets, which are available through many popular retail and online hardware, tool and auto-parts outlets. The PTS Alignment Taps (part # 4935352 SAE; 4935353 metric) and dies (4935058 SAE; 4935059 metric) generally go for between $45 to $55, depending upon the seller, while the Drive Tool set (4935055) ranges from $50 to $60.
