Understanding HDD Tooling for Underground Utility Drilling

An HDD project generally involves creating a pilot bore, enlarging the bore as necessary, and then pulling the product through the completed bore path.

The tooling requirement can change depending on formation conditions, bore diameter, drilling equipment, and the required pullback operation.

For underground utility drilling, primary tooling categories include:

• Drill bits for creating the initial bore
• Tricone and other rotary drilling tools
• PDC fixed-cutter drill bits
• Hole openers and reaming tools for enlarging the bore
• Bit thirds or replacement sections for hole openers
• Jet nozzles and other drilling accessories
• Specialized tooling selected for the formation and application

VBM Drill Bits supplies several of these product categories for HDD and other drilling applications.

HDD Drill Bits: Starting the Pilot Bore

The pilot bore establishes the path that the remainder of the HDD operation will follow. Choosing appropriate drilling tooling for the ground conditions is therefore an important part of the project.

Depending on the application, rotary drilling bits can provide a practical solution for creating a bore through different formations.

VBM supplies tricone drill bits in both steel-tooth and tungsten carbide insert (TCI) configurations. The available range includes sizes from 2" to 36", with sealed and open bearing options and IADC-rated designs.

TCI Tricone Bits for Harder Formations

TCI tricone bits use tungsten carbide inserts on the cutting structure. They are one of the tooling options available when drilling conditions require an insert-style rotary bit.

Formation hardness and drilling conditions should be considered when selecting the appropriate tricone configuration. VBM offers TCI and steel-tooth tricone options rather than treating every formation as requiring the same bit design.

Steel-Tooth Tricone Bits

Steel-tooth tricone bits use milled steel teeth as the cutting structure. They provide another option within the tricone category and can be selected based on the application and formation.

VBM's tricone range includes both steel-tooth and TCI designs, allowing tooling selection to be based on the requirements of the drilling application.

PDC Drill Bits for HDD Applications

PDC drill bits use fixed cutters rather than rotating cones. VBM supplies fixed-cutter PDC drill bits in 3- to 8-blade configurations, with steel-body and matrix-body options.

PDC bit selection can involve several considerations, including:

• Formation characteristics
• Required cutter configuration
• Number of blades
• Bit body material
• Drilling equipment
• Bore requirements

VBM PDC bits use diamond cutters and are available with an API regular pin connection according to the company's product information.

For contractors and drilling-tool distributors, the key point is that PDC and tricone bits are different tooling approaches. The appropriate choice depends on the drilling application rather than a one-size-fits-all recommendation.

PDC vs. Tricone for HDD

For a specific HDD project, tooling should be selected according to the formation and equipment rather than assuming one bit type is appropriate for every bore.

Hole Openers for HDD Pullback Reaming

The pilot bore is only the beginning of many HDD installations. When the pilot hole is smaller than the final required bore, the hole must be enlarged before product installation.

This is where hole openers and HDD pullback reaming tools become important.

VBM supplies hole openers designed for HDD pullback reaming. These can be built with TCI or milled-tooth cutting structures, depending on the application.

TCI vs. Milled-Tooth Hole Openers

The choice between TCI and milled-tooth construction should be based on the ground conditions and intended application.

TCI hole openers use tungsten carbide inserts as the cutting structure.

Milled-tooth hole openers use machined teeth as the cutting structure.

Rather than selecting a hole opener solely because it matches the final product diameter, contractors should consider the formation, existing pilot bore, required enlargement, and drilling equipment available for the job.

Bit Thirds and Replacement Sections for Hole Openers

HDD tooling does not necessarily have to be treated as a single-use assembly.

VBM supplies bit thirds and sections for hole openers and reamers. These replacement components are available for weld-on or bolt-on applications according to the company's product information.

Replacement sections can be useful for drilling-tool distributors and contractors who need to maintain or rebuild hole-opener assemblies.

For operations where hole-opening tooling sees repeated use, replacement cutting sections can also simplify tooling management by allowing appropriate components to be replaced rather than treating the entire assembly as the only available option.

Choosing HDD Tooling by Formation

One of the most important considerations in HDD drilling is the ground being drilled.

Different formations can place different demands on the cutting structure. Tooling selection should therefore consider formation characteristics before the bit or hole opener is ordered.

Formation Hardness

Harder formations can require a different cutting structure than softer formations. TCI, steel-tooth, PDC, and other configurations each have different designs and operating characteristics.

Bore Diameter

The required finished bore diameter influences the tooling needed for the reaming operation. Hole openers should be selected according to the planned bore enlargement and equipment being used.

Drilling Equipment

Connection requirements and tooling compatibility must be considered before ordering. The drill rig, connection, circulation method, and available torque and thrust all influence what tooling can be used.

Pilot Bore Requirements

The pilot bore establishes the foundation for the reaming and pullback stages. Tooling should be planned as part of the complete bore rather than as isolated steps.

Pullback Requirements

The final reaming operation needs to produce a bore suitable for the product being installed. This makes the hole opener or reamer an important part of the overall HDD tooling package.

HDD Accessories and Drilling Support Components

In addition to bits and hole openers, VBM supplies drilling accessories that can support drilling-tool requirements.

The accessory range includes:

• Jet nozzles
• Nozzle wrenches
• Back-flow valves

These components may be small compared with a drill bit or hole opener, but they are part of the broader tooling package used in drilling operations.

Keeping compatible accessories available can also help drilling supply companies and distributors provide a more complete tooling solution to their customers.

Where DTH and Top Hammer Tools Fit

Not every underground drilling application uses the same drilling method.

VBM also supplies DTH hammers, DTH bits, and top hammer bits for other drilling applications.

DTH products include QL, M, and DHD shank DTH hammers, DTH bits matched to hammer shanks, and flat, concave, and convex bit-face configurations.

These products broaden the tooling options available to drilling-tool distributors and contractors serving multiple drilling markets.

How to Build an HDD Tooling Package

For an underground utility drilling project, it can help to think about tooling as a complete sequence:

1. Identify the formation. Determine the ground conditions and hardness relevant to the bore.
2. Define the pilot bore. Select appropriate pilot-bore tooling and connection requirements.
3. Determine the required finished bore. Establish the diameter needed for the product installation.
4. Select the reaming strategy. Determine whether a hole opener or other reaming configuration is appropriate.
5. Select the cutting structure. Choose between available configurations based on the formation and application.
6. Plan replacement components. For applicable hole-openers and reamers, consider whether replacement bit thirds or sections should be included.
7. Confirm accessories and connections. Make sure required nozzles, valves, connections, and other tooling components are compatible before the job begins.

This approach helps turn bit selection from a simple size decision into a more complete tooling plan.

Why Work With a U.S. Drilling Tool Supplier?

For drilling contractors and drilling-tool distributors in the United States, availability can be as important as product selection.

VBM Drill Bits, Inc. is a U.S.-based drilling-tool supplier serving North America and international customers. The company reports stocking more than 100 SKUs in the United States, with dispatch within 24 hours, $100,000 in freight insurance, and a network of more than 40 dealers.

The company serves HDD alongside water well, geothermal, geotechnical/environmental, mining, quarrying, and oil & gas drilling applications.

For distributors, having access to multiple drilling-tool categories through one supplier can make it easier to source tooling for customers working across different applications.

Conclusion

Successful underground utility drilling depends on matching the tooling to the formation, bore requirements, drilling equipment, and pullback operation. From HDD drill bits and tricone or PDC options to hole openers, replacement bit thirds, and drilling accessories, the right tooling package should be planned around the complete bore.

VBM Drill Bits supplies drilling tools for HDD and multiple other drilling applications, giving contractors and drilling-tool distributors access to a broad range of drilling products from a U.S.-based supplier.