How to inspect a used directional drill
| January 09, 2012 |
Buyers of used horizontal directional drills should focus on three critical areas, says Joel D. Nichols, service manager for Ditch Witch of Alabama, Alabaster, Alabama:
The drill frame, including the anchoring – or stake down system and stabilizers.
The power system, particularly the engine and hydraulic components.
And finally, downhole tools, which include the drill pipes, beacon housing, bits and backreamers.
Before you inspect a machine, ask if any maintenance records are available.
Before you start, tap someone knowledgeable to head up the drill inspection. Nichols handily fits that role, with almost 45 years of experience both servicing and selling a variety of Ditch Witch products. “It’s the only job I’ve ever had,” he says. “I went straight home from Vietnam to selling Ditch Witch equipment.”
Our inspection model is a JT2020 with 1,776 hours on it. It’s been installing communication lines, and in its second life could go into a variety of markets, including returning to communication installations, or drilling power, water and sewer lines. Nichols notes that the hours on any drill show actual, hard duty as opposed to other types of construction equipment: “Any time it’s running, it’s usually boring.”
While a new machine typically would be sold as a three-part package – drill frame, mud mixing system and tracking system – used horizontal drilling machines are usually offered solo. “Contractors could have a mud mixing and tracking system from a previous machine that would work with a newer machine so they tend to keep them,” Nichols says.
Before you inspect a machine, ask if any maintenance records are available. This will give you a good idea of the care the machine has received.
A straight frame is critical, and broken frames are difficult to repair. A misaligned frame means undue wear on components.
On both tracks, examine the rollers, bearings, idlers, pins and drive sprockets, looking for excessive wear. Look at the wear on the track cleats, or bar lugs. Replacing a track costs around $3,000, Nichols notes.
The hydraulically powered carriage moves up and down thrusting and rotating the drill pipe during drilling, and pulling back during backreaming. Look for hydraulic leaks on this key component. Move it back and forth with your hands to see if there’s any play in the rack and pinion, which works the carriage forward and back. Look for undue wear patterns on the rack and pinion, which should have an even wear pattern from top to bottom. Make sure the rack and pinion are meshed and aligned.
Check out the drill pipe loading system. Look for hydraulic leaks along the hoses and manifolds. “You’ll know right off the bat if the plastic’s not inside the drill pipe loaders, and they’re inexpensive to replace,” Nichol says. Make sure the front and back pipe loaders are aligned.
During your walk around, always look for hydraulic leaks, usually located at O-rings, fittings and hydraulic lines. Other checkpoints include hydraulic manifolds and hydraulic motors. The good news is that these leaks are easy to detect and inexpensive to repair.
Go to the front of the machine and look at the anchoring system, which secures the machine while boring. While you’ll be operating this system later in the inspection, right now you want to check for hydraulic leaks, whether the shafts are cracked or bent, or there’s a lot of movement when you push the anchor shafts left and right.
Go to the back of the machine and examine the stabilizers on each side, checking for hydraulic leaks on the cylinders, and examining the bushings and pins. Since stabilizers support the weight of the machine while it’s drilling – in the JT2020’s case, about 11,000 pounds – also check the areas where the stabilizers attach to the frame for any signs of stress.
Engines and hydraulics
Look for leaks and examine the engine, fuel and air filters, noting when they’ve last been changed, a date that should be written on the filter canister.
Check for chafing of the hydraulic lines, where they rub against each other and another component. Particularly note the lines coming off pumps and motors.
Evaluate the radiator, and note any trouble signs, including leaking coolant or a crack. Also look at the coolant tanks for leaks.
Check with the drill manufacturer to determine the factory spec outside diameter of the drill pipe. Then use a micrometer to measure the current OD, which will tell you the amount of wear. “If it’s been worn down more than 30 to 40 thousandths of an inch, then you’ll need to look at the cost of replacing the pipes,” Nichols says. “The thickness of the pipe is usually around a quarter inch, so if you take half of that away, it’s going to create problems, especially with all the bending forces these pipes go through.”
Determine how many drill pipes are being sold with unit, since including them is not always a given, and a set of pipes is expensive. The typical 10-foot drill pipe will cost between $300 to $400. With the box on the JT2020 containing 40 pipes, you would be looking at a potential $16,000 in additional costs if they needed replacing.
Check the condition of any beacon housing, bits and backreamers being sold with the machine. Backreamers are used on the pullback phase of a bore to enlarge the hole, so wear will show on both the teeth and the weldments.
The majority of the drill’s functions can be operated with a tethered ground drive system, or lanyard. “These are electronic, so make sure it’s stowed in it’s compartment and in good working condition,” Nichols advises.
Start the drill and listen to the engine, noting any unusual noises. Lower the stabilizers, making sure they can independently move up and down, which is critical for leveling the machine when you’re working on a hillside.
Move the anchoring system up and down, checking for excessive side-to-side motion in the augers and holders on each side. “It will move some,” Nichols says, “but you don’t want excess movement.”
Operate the pipe loader system, loading a pipe out of the box. Evaluate the machine’s rotation, thrust and pullback by rotating left then right, thrusting forward and back.
Get in the operator’s seat and repeat all evaluations. Working the control lever on the right, put the breakout wrench, or vise, through its paces. “Move the lever forward to thrust to make sure the front cylinder is working well, then move it left and right to see the second cylinder working,” Nichols says. Make sure all rocker switches on the control panel are working.
Also note if the previous owner has covers for the instrument panel. “The panel is water resistant, not water proof,” Nichols comments. “Rocker switches don’t like water.”
The on-board water pump, located behind the engine compartment, connects to the external mud mixing system, pumping drilling fluid downhole via the drill string. Check the pump’s hydraulic motor to see if it’s operating well, turns the pump and delivers water out the front of the drill pipe. Look for water leaks around the pump.
Call on experts
Don’t ignore the expertise of local drill dealers when investigating a possible buy, Nichols urges. He gets frequent calls about machines in his territory. Callers ask if he knows the machine, the owner, how regularly it was serviced, and whether or not the owner self performed maintenance.
“Directional drills have gotten to the point where there’s a lot of them out there, and they’ve come down in price in the past decade,” Nichols says. “You can usually get one back into the decent condition by spending $10,000 to $15,000, and have a machine that’s dependable.”
In addition to drill pipe, determine what, if any, backreamers are being sold with the machine. Note the wear on both the teeth and weldments on each backreamer. Also look at the wear on any beacon housing being sold with the unit.
Always look for hydraulic leaks, usually located at O-rings, fittings and hydraulic lines.
Operate the pipe loader system, making sure it smoothly loads and unloads pipe. Make sure the plastic liner is in place, and there are no hydraulic leaks.
Look for leaks and examine the engine, fuel and air filters, noting when they’ve last been changed. Examine the radiator for leaking coolants or cracks.
Measure the drill pipe’s outside diameter and check it against the manufacturer’s factory spec to determine the amount of wear. Make sure you know how many pipes – also called rods – are being sold with the drill.
Make sure shafts are not cracked or bent, there are no hydraulic leaks and there’s no excessive movement when you push them left or right.
Has the instrument panel been protected from the elements by a cover? Do all controls, gauges and switches work properly?
Look at both the left and right track, examining the rollers, bearings, idlers, pins and drive sockets, looking for excessive wear. Look at the wear on the track cleats.
Determine whether the tracks need to be replaced.
Examine the on-board pump’s hydraulic motor, and look for signs of water leaks.
Check the stabilizers on each side, checking for hydraulic leaks on the cylinders. Examine the areas where the stabilizers attach to the frame for signs of stress.
Used Directional Drill Checklist
Number of hours:
Previous owner/application (if known)
General condition, alignment
Cracks or welds?
Anchoring/stake down system
• Hydraulic leaks?
• Shafts straight?
• Excessive movement left and right?
• Hydraulic leaks?
• Condition of bushings and pins
• Cylinder condition
• Any stress evident where stabilizers attach to the frame?
• Rollers, bearings, idler, pins and drive sprocket wear
• Track cleat (or bar lug) wear
• Tensioned properly?
• Hydraulic leaks?
• Rack and pinion:
Unusual wear rack and pinion wear patterns?
• Hydraulic leaks?
• Plastic liner in place?
• Vice wrenches
• Seat condition
• Instrument panel cover?
• Engine, fuel and air filter condition
• Engine, hydraulic oil levels
• Chaffing on hydraulic lines?
• Coolant level?
• Coolant leaks?
On-board water pump
• Percentage of wear
• Number of drill pipe racks?
Check the following with both the tethered ground drive controller and in the operator’s seat:
• Move independently?
Stake down system
• Move augers up and down.
• Load a drill pipe
• Thrust forward/back
• Rotate right
• Rotate left
• Operate breakout wrench vise
• Switches, gauges and levers working?
• Lights working?
• Check oil pressure
• On-board water pump operation
Comments of previous owner or seller Detail any recent repairs and rebuilds and who did them Condition of maintenance records – available electronically? Note any repairs and estimated costs