DHD vs QL vs SD DTH Drill Bit Shanks: How to Choose a Compatible Hammer Bit

One of the most important specifications when purchasing a DTH drill bit is the bit shank.

A drill bit may have the correct diameter but still be completely incompatible with the hammer if the shank design is wrong.

What Is a DTH Bit Shank?

The shank is the rear section of the drill bit that fits inside the hammer.

It is responsible for:

• Receiving piston impact

• Transferring impact energy

• Engaging with the hammer

• Allowing controlled bit movement

• Supporting air distribution and flushing

Common Shank Families

Professional DTH drilling markets use several shank systems, including:

• DHD

• QL

• SD

• COP-type systems

• Other hammer-specific designs

Within each family, different sizes are available for different hammer classes.

For example, DHD-series applications can include DHD340-, DHD350- and DHD360-type configurations, while QL systems can include QL40-, QL50- and QL60-type designs.

Why Compatibility Is Critical

Installing an incorrect shank can cause:

• Failure to install

• Poor piston contact

• Incorrect air distribution

• Abnormal spline wear

• Energy loss

• Premature hammer or bit damage

Never select a bit by outside diameter alone.

Other Factors to Confirm

After confirming the shank, check:

• Required hole diameter

• Hammer size

• Bit face

• Button configuration

• Rock formation

• Air pressure and airflow

YKDRILL supplies multiple DTH bit configurations for international drilling markets, including different shanks, diameters and face designs.

When the exact specification is unknown, buyers should provide the existing hammer model, old drill-bit photos and dimensional information before ordering.

Correct shank identification is the first step toward reliable hammer-and-bit matching.