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PDT18 Earth Drill

40-180 lpm - 2 Speed

PDT18 Earth Drill

40-180 lpm - 2 Speed

Digga PDT18 Two Speed Earth Drill – More Torque. More Speed.

The Digga PDT18 Two Speed Auger Drive delivers serious torque and on-demand speed for machines up to 22 tonnes, supporting up to 180 LPM and 60 kW hydraulic power. Its high-capacity double-stack planetary gearbox offers more torque than the PDT12, tackling tough drilling jobs.

Switch between high-speed, low-torque mode for fast, efficient small-diameter drilling and spoil removal, and low-speed, high-torque mode for large-diameter augers and tough ground. The dual-speed system enhances control, efficiency, and flexibility, enabling a wide range of tasks with one drive.

Featuring Digga’s two-speed orbital motor, precision valve system, and proven gearbox, the PDT18 excels in foundation work, large augering, and heavy-duty drilling, backed by Digga’s industry-leading warranty.

Speeds

2 Speed

Halo Alignment System

Optional / Retrofit Available

Machine Suitability

Mid to Large Excavators - Large Loaders

Ideal Application

Foundation drilling, Large Diameter augering, and Heavy-duty drilling

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Specifications

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Operator's Manuals

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About Trenchers

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FAQs

Features

Two-Speed Drive Get two drives in one: use high speed for quick spoil removal and bore cleaning, then switch to high torque for tough ground or larger augers. This flexibility lets smaller machines deliver high-torque performance without losing speed.

Wider Range of Applications.Handle small and large piling jobs with one drive—use high speed for quick drilling of small diameters and high torque for larger or tougher tasks, all without changing drives.

Lifetime Shaft Pull-out Warranty. Equipped with in-house designed, & manufactured shaft locking nut, this system is guaranteed to prevent shaft pull-out.

Built Tough. Digga gearboxes are renowned for lasting quality and dependability, backed by over 40 years of trusted performance. Precision-machined gears ensure outstanding reliability and a strong return on investment.

Halo: The perfect drilling partner

Halo is the ultimate solution for efficient and precise drilling; designed to save time, reduce costs, and ensure unmatched accuracy. By eliminating the need for a spotter, Halo allows you to reallocate onsite labour to other tasks, or operate autonomously with ease.

Its intuitive operation ensures impressive results, delivering more accurate boreholes and minimising costly hole oversizing. With Halo, you can achieve exceptional returns on your investment and maximise project efficiency. Halo is an indispensable tool for modern drilling operations.

Digga HALO auger drive hero graphic.

Specifications

Built for machines up to 22 tonnes, the PDT18 Two Speed delivers high torque and on-demand speed with its double-stack gearbox and two-speed motor. Handling up to 180 lpm and 60 kW, it’s ideal for foundation work, large augering, and heavy drilling. Switch easily between fast spoil removal and strong torque—two drives in one, without sacrificing performance.

Specifications
Machine Size SuitabilityUp to 18 tonnes
Recommended Flow40-180 lpm
Maximum Torque18,344 Nm
Pressure ValveIncluded
Recommended Auger8 Series 10 Series
Maximum Auger Diameter (Earth)1600 mm
Maximum Auger Diameter (Clay / Shale)1200 mm
Maximum Auger Diameter (Fracturable Rock)1200 mm
Build Information
Overall Length1000 mm
Diameter340 mm
Weight (Without Frame / Hitch)178 kg
Standard Output Shaft75 mm Square
Energy Control ValveOptional
Case Drain RecommendedYes
Maximum Pressure240 bar at 153 lpm
Maximum Flow180 lpm at 204 bar
Maximum Power60 kW (80 hp)
Swing ControlOptional
DiggalignOptional
Halo AvailableOptional
Auger drive specs PDT18 line drawing.

Torque / Speed Charts

Torque chart (Nm)

Pressure (bar)High Torque Output (Low Speed)Low Torque Output (High Speed)
906,9044,610
1007,6715,122
1108,4385,634
1209,2056,146
1309,9726,658
14010,7397,171
15011,5067,683
16012,2738,195
17013,0408,707
18013,8089,219
19014,5759,731
20015,34210,244

Speed chart (RPM)

Flow (lpm)Low Speed Output (High Torque)High Speed Output (Low Torque)
40813
501016
601319
701522
801725
901928
1002132
1102335
1202538
1302741
1402944
1503147
1603351
1703554
1803857

Output speed and torque specifications are theoretical. Speed and torque outputs are dependent on overall system efficiencies associated with the prime mover's hydraulic system. This information should be used for comparative purposes only. When determining criteria, application-specific information is required. please contact DIGGA.

Compatible Augers

A8 Auger

Bladed Teeth
Auger specs A8 line drawing.

RC8 Auger

Tapered Teeth
Auger specs RC8 line drawing.

RC10 Auger

(16mm Flight Material)
Auger specs RC10 line drawing.

DR8 Auger (2m OAL)

Rotating Rock Picks
Auger specs DR8 line drawing.

Extensions

(X075HD)

Digga’s Heavy-Duty Drilling Extensions increase drilling depth by coupling directly to the auger drive hub and gearbox output shaft. Available in various lengths, the 75mm square Heavy-Duty Series is rated up to 22,000Nm of torque and uses fixed outer extension configurations. Heavy-duty gussets and a precision-machined flange ensure a secure, long-lasting connection for demanding conditions.

XO75HD extensions feature integrated lifting eyelets, allowing the extension or auger to be safely suspended in the hole. This enables operators to add or remove extensions as needed, making it possible to drill deeper holes beyond the lift height of the host machine. All Digga extension types are available in multiple lengths to meet the specific demands of your jobsite.

Extension Specifications

Maximum Torque23,000 Nm
Standard Hub75 mm Square
Body (Outer)Heavy Duty Tube - Fixed Lengths
Lengths1000 mm / 1500 mm / 2000 mm / 2500 mm / 3000 mm / 3500 mm / 4000 mm / 4500 mm / 5000 mm

MY.DIGGA.COM

Find everything you need for your Digga attachment - Including operator manuals, safety information, risk assessments, electrical guides, maintenance tips, and 'how to' instructions. Our user-friendly interface and easy navigation ensure that you can quickly access the support and information you need.

LEARN MORE ABOUT EARTH DRILLS

From understanding the different types of earth drills available, to learning about components and maintenance, we hope you find this information helpful.

FREQUENTLY ASKED QUESTIONS

What earth drill best suits my machine?

General rule of thumb would be that your machine weight matches the model code of the earth drill.

i.e. 2 Tonne Machine – PDX2, 3 Tonne – PD3, 5 Tonne – PD5, etc., etc...

Your application and expectation would be the next governing factor.

i.e. For a 5 Tonne machine

The standard model reference of PD5 would best suit augering in general conditions of soil, clay, shale up to approx. 900mm.

Should your main drilling requirement only be for softer ground conditions with smaller diameter augers, e.g. sand and soil with augers up to 600mm dia., then you may consider stepping down a model size to a PD4-5, (-5 denotes 75mm Square Output Shaft to match the recommended Type 6 Auger Bits). This step down in model will give you more auger speed while still maintaining enough power to cope with the down-pressure of the 5 Tonne machine.

Likewise, if your application requires larger dia. holes or harder condition, i.e. rock, then stepping up a model or two, PD6 or PD7 may best suit these applications.

What is the biggest earth drill I can put on my machine?

There is a several factors that are at play when suiting up “The Biggest earth drill” consideration needs to be given to:

  • Lift capacity of the host machine: should the weight of the drill exceed the SWL (safe Working Load) of the host machine then the drive should not be fitted.
  • Ground clearance: Careful consideration needs to be given to insure there is ample ground clearance under the pickup of the host machine when both the drive and drilling tool or Screw Pile are fitted.
  • Application Overview: When selecting the largest drive, it's essential to consider both the desired outcome and the specific job requirements. These factors will significantly influence the choice of the appropriate drill.
What is kW and why does it Matter?

Every hydraulic motor fixed to a planetary gearbox has a listed maximum power (kW) rating. Exceeding this rating will cause motor damage and failure.

Power is created by combining pressure and flow. You may increase pressure while reducing flow, or increase flow while reducing pressure – maximise both simultaneously may exceed the motor's safe operating limits. The kW Power can be calculated with the following formula (kW) = Flow (litres/minute) × Pressure (bar) ÷ 600

Operating outside the rated kW will cause:

  • Excessive heat buildup, degrading hydraulic fluid
  • Internal seal and shaft damage
  • Motor seizure and failure
  • Costly downtime and replacement
What happens if put the wrong drive on my machine?

If you install the wrong planetary earth drill on your machine, several issues could arise, potentially affecting performance, safety, and the longevity of both the drive and the machine:

  1. Incorrect Torque and Speed: The earth drill may not be suited to the hydraulic flow and pressure of your machine. This can result in too much or too little torque, either leading to inefficient digging or overstressing the drive components leading to frailer.
  2. Reduced Efficiency: The wrong drill might not be optimized for your specific drilling conditions, causing slower digging and increased wear on the auger teeth and pilot, leading to more frequent maintenance.
  3. Hydraulic System Strain: Using an incompatible drive could place excessive strain on your machine's hydraulic system, potentially causing overheating or damage to pumps, hoses, and other components.
  4. Poor Performance: If theearth drill is mismatched, it may not provide the required torque or rotational speed for your ground conditions, leading to subpar hole performance, especially in difficult ground.
  5. Increased Wear and Tear: An incorrect drive can accelerate wear on both the drill and the auger, leading to more frequent breakdowns or even failure, which can be costly and time-consuming to repair.
  6. Safety Hazards: A mismatched drive may cause unexpected behaviour, such as uncontrolled movements or failure under load, which could create a safety risk to operators, bystanders and equipment.

For optimal performance and safety, it's crucial to match the earth drill to your machine's specifications and the ground conditions you are working in.

What are the advantages of a 2-speed earth drill?

A 2-speed drill offers enhanced versatility and efficiency for drilling applications by providing two selectable speed ranges:

  1. High Torque (Low Speed): This setting is ideal for drilling through hard, compacted ground, clay, or rock. It delivers maximum torque, allowing the auger to cut through tougher materials with greater force, though at a slower speed.
  2. High Speed (Low Torque): This setting is suited for softer soils, such as sand or loam, where high torque isn't necessary. It allows for faster drilling, increasing productivity by completing holes more quickly in easier ground conditions.

Benefits of a 2-Speed Drive:

  • Versatility: Allows you to switch between speed and torque depending on the ground conditions, making it suitable for a wide variety of drilling environments.
  • Efficiency: Saves time and wear on equipment by using the appropriate speed and torque for each specific task.
  • Enhanced Versatility and Performance: Engineered to handle both hard and soft soils, this design allows for the integration of a larger reduction gearbox, delivering increased torque without compromising speed. Enjoy the performance benefits of two earth drills in one, eliminating the need for equipment changes and significantly boosting overall job efficiency.

In short, a 2-speed drill offers greater diversity, control, and adaptability, ensuring optimal performance and productivity across different drilling conditions.

Can one earth drill fit both my machines?

It is possible to get an earth drill that can be used with two different size machines, but it will depend on the specific earth drill and the machines you have. If your two machines are close in size, for example a 5t and 10t or 15t and 20t but the drill must be suited to the larger machine, it is not feasible should you have a 3t and 20t machine as the physical size of the drive for the 20t machine is far too large for the 3t machine and the performance output would be inadequate to perform normal drilling.

Some earth drills are designed to be used with a range of different machines and may come with adaptors or other attachments that allow them to be used with different sizes of equipment. However, it's important to check the specifications of the earth drill and the machines you must ensure that they are compatible.

Additionally, it's important to consider the power and torque of the machines, and the size and weight of the earth drill. A larger or heavier earth drill may require a more powerful machine to operate, and a smaller machine may not be able to handle the weight and torque of the earth drill.

It's important to consult with the manufacturer or a professional before deciding, and to check the compatibility and capacity of your machines with the earth drill you want to use.

The other option that is idea for this scenario of running one drive two machines is a two-speed drive (see 2- Speed high flow & 2-Speed STD flow).

Will my 1.0Tonne machine dill a 600mm Dia. hole in solid rock?

In general, we would have to say NO - For the following reasons:

  1. Without knowing the grade of rock, e.g. for sandstone there are 5 grades, 1 – being soft and weathered, classed as drillable, and 5 – being extremely hard and classed as un-drillable.
  2. The physical downforce of your machine will not carry enough weight to functionally drill this diametre. hole in rock.
What is the difference between a PD5, PD6 & PD7?

There are several differences between a PD5 & PD6, PD7

The main is the amount of torque outputted by each individual unit PD5 Max. Nominal Torque @ 240bar Pressure is 5000 Nm., PD6 – 5,500 Nm & PD7 – 6,000 nm.

With each increment in increase of torque you have an equal decrease in output shaft speed when inputting the same amount of flow (Lpm or Gpm).

Additional differences between the PD5 and the PD6 & PD7 is the gearset of a PD5 has a Series 2 Gearset where the PD6 & PD7 have a series 4. This difference is in the thickness of the gearsets in each. These differences are there to cope with the increasing weight of the parent machine and for the increase in torque capabilities.

Also, there is a marked difference in the bearings size of the PD6 & 7 over the PD5. The increase in size of the bearings in the PD6 & 7 is to cope with the increase in weight from the parent/host machine.

What is better, Round, Square or Hex Shaft?

Depending on the torque output of the drive unit we would recommend a square or hexagonal shaft for all drives over 4,500 Nm. For drives under this torque rating a 65mm Rnd as standard relies on the auger pin to bare the rotational load of the drive unit. This pin is rated to 10Knm but with our safety factor we like to step up to Sq or hex for torques higher. By using sq. or hex we are supporting the rotational load of the drive on the four side of the square or the 6 sides of the hex.

Why does my earth drill need servicing?

The gearbox of earth drills sit in their own bath of oil. The gearbox is not lubricated by the machines hydraulic oil, as a result the oil needs regular changes similar to your car.

Service intervals are outlined in the operator’s manual provided with all Digga attachments. The recommended intervals depend on the intensity of use, ranging from occasional to extreme. For best practices, consult the manual to determine the appropriate maintenance schedule based on your specific usage.

Regular servicing is essential to maintain performance and extend the life of your equipment as well as your warranty.

What oil do I use in the gearbox?

Depending upon the earth drill model being used and its application with determine the type of oil to be used, but in all drive, we recommend using and “EP” (Extreme Pressure) oil this will ensure longevity of your gearbox. Typically, your drills will come from factory filled with:

  • ISO EP320 Mineral Oil ... for PDD to PD50 including 2 Speed drives
  • ISO EP320 Synthetic oil ... for SD, MD, UD, XD drives

Note : if unsure please contact the Digga Service department for guidance

Can I fit HALO on a competitor's earth drill?

You can't use the Digga HALO system on non-Digga earth drills because the HALO system is specifically designed and engineered to suit Digga earth drills.

Here are some key reasons:

  • Compatibility: The HALO alignment system is built to integrate seamlessly with Digga drills, ensuring correct fitment and performance. Competitor earth drills may have different dimensions, or operational requirements that aren't compatible with the HALO system.
  • Calibration: HALO uses 6 sensors to provide real-time feedback on the auger’s angle for precise drilling. These sensors are calibrated to work specifically with Digga’s drills and control systems.
  • Warranty and Support: Digga products, including the HALO system, are covered under specific warranties when used with compatible Digga components. Installing HALO on a non-Digga drive will void warranties,

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