This type of tap displaces the material instead of cutting while threading _______.

Explanation:

Machine taps:

The two important features of machine taps are:

• Ability to withstand the torque needed for threading holes.
• Provision for eliminating chip jamming.

Types of machine taps:

Thread forming taps (Flute-less taps):

• These taps form threads in the hole by displacing the material and not by cutting action.
• These taps have projecting lobes which actually help in forming the thread.
• Since there are no chips in the process, it is very valuable in places where chip removal poses problems.
• These taps are excellent for tapping copper, brass, aluminum, lead, etc.
• The thread finish is also comparatively better than in the fluted taps.

Gun tap (Spiral pointed tap):

• These taps are especially useful for machine tapping through holes.
• In the case of blind hole tapping, there should be sufficient space below to accommodate the chips.
• While tapping, the chips are forced out ahead of the tap.
• This prevents the clogging of the chips and thus reduces the chances of tap breakage.
• These taps are stronger since the flutes are shallow.
• The flutes of these taps do not convey chips.

Flute-less spiral pointed tap (Stub flute taps):

• These taps have short angular flutes ground on the chamfered end, and the rest of the body is left solid.
• These taps are stronger than gun taps.
• Flute-less taps are used for tapping through holes in materials that are not thicker than the diameter of the holes.
• Flute-less spiral point taps are best suited for tapping soft materials or thin metal sections.

Helical fluted taps/fluted spiral taps:

• These taps have spiral flutes that bring out the chips from the hole being tapped.
• These are useful for tapping holes with slots.
• The helical land of the tap will bridge the interruption of the surface being threaded.
• The helical flutes of the tap provide a shear-cutting action and are mostly used to tap holes in ductile materials like aluminum, brass, copper, etc.
• Spiral fluted taps are also available with fast spiral.
• These taps are best suited for tapping deep holes as they can clear the chips faster from the hole.