IADC Member log

What does the IADC Code Mean?


IADC code is short for “International  Association of Drilling Contractors”.


The IADC Code for Tricone Bits defines its bearing design and other design features ( SHIRT TAIL, LEG, SECTION, CUTTER).

IADC Codes make it easier for drillers to describe what kind of rock bit they are looking for to the supplier.

The most common IADC code used in HDD is such as 127, 517, 637 etc.  Let us check what does it stands for.


first digit IADC code
  • 1, 2, and 3 designate Steel Tooth Bits with 1 for soft, 2 for medium and 3 for hard formations.
  • 4, 5, 6, 7, and 8 designate tungsten Carbide Insert Bits for varying formation hardness with 4 being the softest and 8 the hardest.


Second Digit IADC code

1, 2, 3, and 4 help further breakdown the formation with 1 being the softest and 4 the hardest.

IADC 126 Steel Tooth Tricone Bit


Third Digit IADC code

This digit will classify the bit according to bearing/seal type – see information on different bearing types – and special guage wear protection as follows:

  1. Standard open bearing roller bit
  2. Standard open bearing roller bit, air-cooled
  3. Standard open bearing roller bit with gauge protection which is defined as carbide inserts in the heel of the cone
  4. Sealed roller bearing bit
  5. Sealed roller bearing bit with gauge protection
  6. Journal sealed bearing bit
  7. Journal sealed bearing bit with gauge protection
Tricone bearing type illustration


The following letter codes are used in the fourth digit position to indicate additional features:

A. Air Application
R. Reinforced Welds
C. Center Jet
S. Standard Steel Tooth
D. Deviation Control
X. Chisel Insert
E. Extended Jet
Y. Conical Insert
G. Extra Gage Protection
Z. Other Insert Shape
J. Jet Deflection

The Corresponding Parameters of IADC for commonly used pilot bits

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