Spiral Pointed - Plug & Spiral Flute.
Used for efficient chip disposal in production tapping operations. Available in sizes thru 1/2".

Spiral Pointed - Plug (4 Thread Chamfer). Incorporates an angular grind at the point end of the tap which shears chips and drives them forward of the tap. Used widely in long thru holes and blind holes with ample chip clearance. They are free cutting and provide increased tap strength. Not recommended for abrasive materials.
Unit of Measure


On Hand

N/A {0}

Thread Size

N/A 7/16-20


N/A Plug

Thread Size Inch

N/A .438 in

Class of Fit

N/A 3B

A - Length Overall

N/A 3.375 in

B - Thread Length

N/A 1.656 in

C - Length of Square

N/A .438 in

D - Max. Shank Diameter

N/A .367 in

Max. Size of Square

N/A .275 in

Number of Flutes

N/A 3

Tap Style

N/A 3

H - Limits

N/A H3

N/A Special STI Taps
Taps made to different limits, configurations, or to cut difficult materials, or for very high production are available upon request. The following data should be provided at the time of ordering:

  • Thread size
  • Class of fit. Example: 3B, 2B, Special Size to Special Tolerance.
  • Material to be cut, and its hardness.
  • Hole configuration. Example: Thru or Blind including length of drilled and tapped hole.
  • Type tap. Example: Plug or Bottoming Straight Flute, Spiral Point, Spiral Flute.
  • Special features. Example: Length, Shank Diameter, Chamfer Length, Tap Material.
  • Special coating of tap.