CoilThread STI Taps

CoilThread® STI (Screw Thread Inserts) Taps are designed specifically to create internal threads that will accommodate a  CoilThread® insert. CoilThread® Taps can be used in a range of materials including aluminium, magnesium, steel, plastics and other free machining materials. CoilThread® Taps are manufactured from High Speed Steel for durability and prolonged tooling life.

Features & Benefits

  • STI Taps can be used for both Tangless® and Tanged CoilThread® inserts.
  • Available in 3B and 2B (Unified) or 4H and 5H (Metric) Class of Fit.
  • Available for a full range of Unified and Metric thread sizes.
  • Lower cost than similar taps from competitors.

We offer four STI tap styles for various applications:

Plug Style

Plug Style 4-Thread Chamfer

(4-Thread Chamfer)

Easy starting for through-holes and blind holes.

Bottoming Style

Bottoming Style 2-Thread Chamfer

(2-Thread Chamfer)

Ideal for blind holes that are drilled to a minimum depth.

Spiral Pointed Plug

Spiral Pointed Plug 4-Thread Chamfer

(4-Thread Chamfer)

Free-cutting for use in long through-holes and in blind holes with chip clearance.

Spiral Flute Bottoming

Spiral Flute Bottoming 2-Thread Chamfer

(2-Thread Chamfer)

Designed to pull chips out of deep or blind holes in soft materials

Part Numbers

Example of an STI Taps part number:

CT C - 02 SRP - H1

1  2     3    4      5

Tool Type
Thread Designation
Size Designation
Style / Type
Class of Fit
CT - CoilThread® Tap (STI) C - Unified Coarse
F - Unified Fine
M - Metric
--- SRP - Standard Regular Plug
SRB - Standard Regular Bottoming
SPP - Spiral Point Plug
SFB - Spiral Flute Bottoming

Example 2 of how to put together a tool's part number. 
Tangless® or Tanged Tool Type of Tool   Metric Size Free Running or Locking
Blank= Tanged CT


Insertion Tool M 2.5-12 F= Free Running
2= Tangless®           L= Locking


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