Review: Grundopit pit drill

By: The Ed

Date: 17.09.2014

Hydraulic braces anchor the unit in place. Grundopit pit drill

The Grundopit 40/60 measures 1120mm in length. Grundopit pit drill

A Vanguard V-twin unit powers the directional drill. Grundopit pit drill

Drill heads and stems ready for action. Grundopit pit drill

Hydraulic braces anchor the unit in place.

The Grundopit 40/60 measures 1120mm in length.

A Vanguard V-twin unit powers the directional drill.

Drill heads and stems ready for action.

Chances are many readers have not heard of a pit drill. I know that when I was told that Worthington Contractors in Christchurch was looking at selling its one, I had to get along for a look.

Having not encountered a pit drill before and not wanting to sound like a dork, the first thing I had to do was school myself up on exactly what a pit drill was, and what it was capable of. Videos and literature courtesy of the world-famous internet quickly gave me the necessary information required and an appointment was made to view the machine in action.

Brief description

Pit drills are directional drills with a difference. Unlike the traditional pieces of kit, which we commonly see around the country (being mounted on tracks), the pit drill is a trackless unit that gets lowered into (you guessed it) a pit. By doing this, the 'lead' is reduced, meaning that the unit can be used on tighter and hilly sites, or where space is at a premium.

Actually, just to make things a bit clearer about 'lead', what I mean is a traditional directional drill has to bore down from above ground to reach the correct height the drilling is to commence at. As the drilling is carried out horizontally, a 'lead' of say 15 metres may be required before the drill head is deep enough to continue on the correct plane. As you have probably quickly worked out, the digging of a hole to the correct depth and placing a directional drill in the hole will negate the need for a 'lead'. Got it? Good.

The advantage

The bonus I can see is you could drop a pit drill in alongside a building and drill through to supply services or use it to work in urban places, such as small sections. This machine should come in especially handy if certain things have been left off the plan by the architect. Another handy use for a pit drill would be working on a hill, where a 'lead' would be difficult to achieve.

Uses

Made by TT Technologies in the USA, the company has been producing trenchless technology for over 45 years. According to its manufacturers, the Grundopit 40/60P can be used to install water services, electrical conduit, gas services, and communication lines in tight working conditions. The unit delivers 5980kg of thrust, 3990 kg of pull-back, and 599Nm of torque, with a bore length of up to 49 metres.

The unit

Size-wise, the Grundopit 40/60P is a very compact unit at 1120mm long. While sturdy in construction, it is light enough (200kg) to be lifted in a pit by three or four able-bodied people, although recommendations are it's lowered into the ground with a machine.
Four hydraulic supporting braces anchor the unit in place.

Power to the drill unit is provided by a 13kW (18hp) Vanguard V-twin, four-stroke power pack which is used to pressurise the hydraulic system. I guess this plant could be used for alternative duties when the pit drill is not being used.

The last piece of the unit is the water tank and pump. This provides pressure at 5980kPa (857psi).

The complete unit of drill, power pack, and water pump is small enough to be carried on the back of a work ute.

The pit drill at work

For demonstration purposes, Worthington Contractors has kindly excavated a small pit at the rear of its central city yard and the pit drill is ready to work by the time I arrive. A 2.5-tonne excavator was used both to excavate and lower the drill into the hole.

After a look over the unit and an explanation of its features, the power pack gets fired up. Then it is a simple matter of carefully using the controls to manoeuvre the drill head through the sandy sub-soil and connecting on new drill stems as it steadily advances forward. In ground like this, the drill makes pretty easy work, but I should imagine in harder ground, timber would need to be placed in the pit for the hydraulic legs to anchor against.

Unlike a traditional directional drill, the Grundopit 40/60P pit drill uses smaller drill stems, measuring 610mm in length. Worthington's says it has enough stems to drill around 30 metres at a time.

Actually, watching the unit in action substantially de-mystifies the whole directional drilling world for me, as the pit drill is a machine with its workings fully-exposed for all to see.

Summary

Worthington's tells me this unit has very low hours on the clock, and is now surplus to requirements, due to its busy workload on other Christchurch jobs.

With its availability, I see this machine as being suitable for a contractor wanting to dip their toes in the water and try out the directional drilling scene, or perhaps an existing driller who needs a piece of gear to complement their current fleet.