G-Oversize HHS Tap

The G-Oversize HSS Tapered Tap is a High-Speed Steel (HSS) Tapered Tap designed for installing Irontite “GO” series tapered, threaded plugs in casting repair, particularly in high-pressure and high-temperature areas like valve seats and water directors in GM/Detroit Diesel 71 and 92 series engines.

The G-Oversize HSS Tapered Tap, also described as an “HSS Tapered Tap GO,” is a specialized tool used for installing Irontite tapered, threaded plugs in various casting repair applications. Its design makes it particularly suitable for areas subject to high pressure and temperatures, such as valve seat regions and water director installations in GM/Detroit Diesel 71 and 92 series engines.

As a tapered tap, this tool cuts threads along its entire length. When working with thick metal castings, it is recommended to first ream the hole with a tapered reamer before using this tap. This pre-reaming helps to ensure a reasonable lifespan for the tap. Applying consistent downward pressure during the tapping process is important. For larger tapered taps used in heavy-duty diesel engine injector seat area repair, Irontite offers lead screw nuts and arbors to aid in applying the necessary pressure.

The use of a quality tapping fluid is mandatory with this tapered tap. Irontite recommends their TAP-O tapping compound, available in 8 oz (468-9920-08), ½ gallon (468-9920-64), and 5 gallon (468-9926-40) sizes, to ensure smooth cutting and optimal thread quality.

Irontite tapered taps, including this G-Oversize tap, and their corresponding plugs are engineered to create a tight, thread-to-thread fit when the plugs are torqued into the tapped holes, ensuring a secure and reliable seal.

This specific G-Oversize HSS Tap is designed for use with the following “GO” type ductile iron plugs:

• GO (452-2608-40): Features a thread length of 1 7/16 inches and a small end diameter of 0.590 inches.
• GO-3 (452-2608-43)
• GO-4 (452-2608-44)
• GO SHORT (452-2608-55)

These “GO” series plugs have varying specifications, including specific hole sizes required for drilled versions.