AMSUO Spiral-Point (Gun) Taps — HSS-E Cobalt, TiN Coated, UNC/UNF Inch Series, for Through Holes

Push chips ahead of the tap and out of through holes

Spiral-point taps drive the chip forward and out of the far side of the hole, so you never have to reverse the tap to break or clear it. Threads come out cleaner and the pass finishes faster — this is the tap to reach for whenever the hole goes all the way through.

Why it works

The tip carries a short ground spiral point that pushes the chip ahead of the cutting edges instead of packing it into the flutes. Also called gun taps, these are the standard choice for through-hole production tapping, whether you drive them by hand or in a machine spindle.

• Best for: through holes, machine and hand tapping, production runs
• Not for: blind holes — the chip needs somewhere to go
• Thread forms: UNC and UNF inch series, right hand

Material and coating

HSS-E (cobalt high-speed steel) — added cobalt raises hot hardness, so the cutting edges hold up in stainless steel and higher-tensile steels where standard HSS softens.

TiN coating (gold) — a hard titanium-nitride layer lowers friction at the cutting edge, which means lower torque, less galling in gummy materials, and a longer service life than an uncoated tap.

Size range and recommended tap drill

Tap drill sizes above are the standard published values for approximately 75% thread engagement. Flute count runs 2 to 4 depending on thread size. Pitch diameter limit is standard inch-series fit (H2 class). Other thread sizes, left-hand threads, and metric series are available on request.

Related tooling

Prepare the hole — drill with the recommended tap drill first, then chamfer the opening so the tap starts cleanly.

Hold the tap — a tap wrench sized to the shank and square drive end gives you the leverage to keep the tap turning and the chips moving.

Keep it square — a tap guide holds the tap perpendicular to the surface for the first few turns, which is where most broken taps come from.

For use on

Steel, stainless steel, cast iron, aluminum, brass, bronze, copper, and most plastics. For hardened or abrasive materials, a carbide tap is the better choice.