The underground construction industry is in the midst of another fiber boom that is not only keeping experienced contractors busy but also has drawn many new people into the installation business.
No matter their level of experience, all horizontal directional drilling (HDD) contractors would benefit from being more knowledgeable about tooling — a vital yet often underappreciated part of any project.
“Tooling is important to help maximize your productivity,” said Cody Mecham, Vermeer cutting edge product manager. “Having the right tooling for the right ground condition will assist in increasing the drilling speed, accuracy and steering.”
This goes for all HDD jobs, but Mecham has seen some interesting trends with the use of tooling on fiber installations.
One of those is more and more contractors are not doing a backream. Fiber is such a compact product and the holes are so small — typically 8 inches (20.3 cm) or less — that crews are shooting and pulling the product right back.
“Having the right tooling for the right ground condition will assist in increasing the drilling speed, accuracy and steering.”
A lot of fiber work is occurring in areas with rock or cobblestone, so contractors are seeking tools that can help them bore those smaller holes quickly in aggressive ground conditions. When a backream is necessary, contractors are asking for reamers that work well in rock but are 6 or 8 inches (15.2 or 20.3 cm) in diameter, which is smaller than is typical for that piece of tooling.
“It can be a challenge for a contractor to find a manufacturer that will offer reamer in that size,” said Mecham.
Vermeer has custom-made hole openers for contractors, but in the past there hasn’t been a huge demand.
Stocking your “toolbox”
Contractors new to directional boring or to the fiber market may wonder what pieces of tooling should be in their toolbox. A good local dealer will have the expertise to help. An OEM tooling manufacturer is also a good source of information.
The core pieces of the drill string don’t change for fiber jobs, according to Mecham. You still need a drive chuck and/or sub savers (machine dependent), a sonde housing, a bit, puller, swivel and, when conditions require it, a reamer. Those tools should be able to accommodate the 8-inch-or-smaller (20.3 cm) holes common in fiber installations.
A modular system that can be used in different applications can be an advantage in the fiber market because many contractors travel regionally or even nationwide for work.
“Purchasing a system that encompasses both their housing and their bits so they have a go-to for all ground conditions is something we recommend as a good long-term investment,” explained Mecham. “The fiber boom requires contractors to be very mobile.”
In addition to small holes, HDD tooling for fiber jobs often must be able to accommodate tighter work spaces above ground and below. Many fiber jobsites are in areas where there is existing infrastructure, oftentimes in crowded urban settings.
“When you’re trying to navigate alongside existing utilities with a very small hole, you need to be much more finite,” said Mecham.
Small footprints create tooling decisions
Another important consideration is to select tooling designed to have robust connection points, especially when working around existing infrastructure. It’s important to match the right tooling to the angle of your entry point.
A connection system that can be changed quickly and efficiently is also beneficial when space is constricted. Vermeer, for example, offers the QuickFire® connection system, which allows connections to be made with just a few turns rather than the 15 turns common with other systems.
Some contractors are trying to select the smallest horizontal directional drill that can fit in the footprint for the job, which can max out that smaller machine to its full capacity. That can put a lot of stress on the connection points.
“This adds to the importance of regularly inspecting connection points and selecting high-quality materials,” said Mecham.
Excessive wear may be a sign that those parts are being run too hard, or that their quality is lacking. Contractors sometimes will buy less-expensive tooling, but if a piece is poorly designed and made out of low-grade materials, it may cost the contractor more in the long run.
Ground conditions dictate tooling choices
When it comes to selecting tooling for certain ground conditions, contractors need to remember that every bore is different and tooling decisions should be made on a job-by-job basis. Generally speaking, Mecham has this advice:
Rock and gravel — Steering is often the biggest challenge in rock and gravel. In gravel, try to use a bit that allows for a nice scooping action to move the material out of the way. In rock, you’ll want a piece designed to provide a clean cutting action.
Excessive wear is also an issue in rock and gravel. Look for a bit with carbide to help it last. The same goes for the housing; carbide can help reduce wear and protect it from the powerful conditions that occur underground.
Also with the housing, look at the design of the lid. It should have a pin system or some other type of structure to ensure the lid stays in place once it encounters the pressure and bouncing that occurs in rock and gravel.
Sand — Sand is very abrasive, so drilling fluid becomes even more important. Proper fluid flow through the sonde housing is necessary to reduce the chance of overheating and wear by carrying cuttings or sand away from the housing itself. Like gravel, having a bit with a scooping action is helpful.
Clay — Fluid management also is very important with clay because of its composition.
“It’s nasty material,” said Mecham. “You need a lot of fluid exactly when you want it. But you also cannot have too much.”
Tooling should be selected that allows for pinpoint accuracy in directing fluid.
No matter the ground conditions, contractors should also pay attention to how many nozzles are on a reamer and the direction they are facing.
Don’t underestimate tooling
These are just a sampling of ground conditions. Whatever the situation is downhole, it’s important not to underestimate the importance of tooling. Yet Mecham sees that happen again and again.
“You’d be surprised how many times you visit a jobsite and the crew has all of this equipment set up, but they don’t have all the pieces of tooling they need,” he said.
That may lead to wasted time, which besides putting the contractor behind schedule on that job and at risk of not meeting contractual obligations, can give the contractor a reputation that may affect his future ability to get jobs.
Mecham has a theory for why this happens. Uncertainty is part of the nature of horizontal directional drilling. Each day is different; you’re never completely sure what is downhole or a bore plan may change. Contractors and crews are almost conditioned to deal with the unexpected. So they don’t always give the proper forethought to tooling selection.
To correct this, Mecham believes communication is important. Make sure tooling is part of pre-bore planning and that someone is responsible for tooling. This can be especially helpful in the fast-paced world of fiber installations.
“Picking the right piece of tooling is just as important as selecting the right drill for the bore,” stated Mecham.
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