• 5318 Victory Drive
    Indianapolis, IN 46203
  • (800) 622-4824
  • www.haggard-stocking.com

5/16-24 Tap, Modified Bottom, UNF STI thread, H3/H4, 3 flutes, HSS-E, TiN Coated, 40° Spiral Flute

  • Item Code: 3989-7.938
  • Brand: Guhring
  • Unit Size: 1

Description

An STI tap thread tap is designed to create an oversized thread to accommodate the required Heli-Coil insert. Screw Thread Inserts (STI) are helically formed diamond shaped stainless steel or phosphorous bronze wire that screw into a threaded hole to form a mating internal thread. Screw thread inserts are a convenient way of repairing stripped out threads and are also used to provide stronger threads in softer materials than can be obtained by directly tapping the base metal.

Tech Specs

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Overall Length (mm) 74.5998
H Limit H3/H4
Reach (decimal) 1.4570
Series 3989
Coating TiN
Number of flutes 3
Brand Guhring
chamfer (decimal) Modified Bottom
threadtype UNF STI
Diameter 5/16-24
Shank Diameter (mm) 9.6774
Diameter (mm) 7.938
Helix Angle 40°
Material HSS-E
Overall Length (decimal) 2.9370
Square Size (decimal) 0.2382