The Ditch Witch organization manufactures the most durable drill pipe in the underground construction industry. But even the most dependable pipe depends on you to use it properly. Yes, it's solid steel and manufactured with the utmost precision, but one false move—exceeding the pipe's bend radius, clamping on the body of the pipe, insufficient thread lubrication—and you can quickly ruin not only an individual pipe but also an entire drill string.

Pipe isn't cheap, as experienced horizontal directional drilling (HDD) professionals know well, nor is the downtime associated with replacing it, so it definitely pays to follow instructions in the operator's manual to the letter. Most HDD operators have learned how to execute a successful bore by making mistakes along the way. Sometimes experience is the best teacher, but by taking the following tips to heart, maybe you can avoid learning the hard way.

Before The Bore.

Proper drill pipe care starts long before you reach the jobsite. First, select a pipe designed for your drilling rig, keeping in mind that:

•  Simply selecting a tool joint that will function in the grippers is not enough. The tool joint must be designed to match the rig's output torque or it won't tighten correctly.
•  The outside diameter of the pipe greatly influences its steering characteristics. Too-large or too-small pipe bodies will not properly match the thrust and may create steering problems.

The bore should be thoroughly planned before unloading the rig. Take into consideration what buried hazards or obstacles exist on the jobsite (where and how deep they are), the size and type of material to be installed, the bend radius of the material and how deep it must be placed, your setup position and entry angle, and if the job allows entry and exit pits.

You'll want to use the lowest possible entry angle to minimize the bending necessary to drill horizontally at the proper depth; entry and exit pits help prevent sharp bends at these points, and allow the cutting tool to start without skidding and bending the pipe.

If you are using brand new pipe, perform the following preconditioning procedure three times for each pipe before first use:

      1. Hand-lubricate the entire surface of threads and shoulders of both ends of the pipe with the recommended copper-base tool-joint compound.
      2. Join the pipe and tighten the joint.
      3. Break the joint.

Failure to follow this procedure could result in fused joints and pipe damage. And remember to precondition new saver subs the same way you do new pipe.

During The Bore.

Both the drill pipe and the material to be installed have bend radius limits that you must know and never exceed. The maximum bend radius allowed for your Ditch Witch drill pipe is shown in a chart in your operator's manual. The product to be installed often has a bend radius different than the drill pipe, so the pilot bore should be planned for whichever has the greater bend radius.

How you make up and break apart tool joints greatly affects the life of your drill string. Before connecting drill pipe, lubricate the threads and shoulders of male joints with a copper-base tool-joint compound. This prevents rust and reduces wear on shoulders and threads. When necessary, clean the threads with high-pressure water and detergent. (Do NOT use gasoline or other petroleum-based solvents, as this will prevent the tool-joint compound from sticking to the joints and reduce thread life.)

Connecting and disconnecting joints should always be performed slowly and deliberately. Always carefully align the male and female ends of pipe before screwing them together. Poor alignment can damage the threads and destroy the usefulness of the joint.

Carefully time the rotation with the carriage travel speed. This will help prevent thread crossing, galling, and shoulder swelling. Tapered threads don't fully engage until the last 1/16 of an inch, so make sure the shoulder faces are touching and then tighten the joint with full machine torque.

Never rush the job by letting the ground finish making up the joint. This will not provide sufficient torque to make a good connection.

Of all the joints in a drill string, those just behind the drill bit take the highest stress. The lead pipe is in the ground longer, and gets more shockloads and rotation cycles. Use a transition sub between the tool and the first drill pipe to absorb shock.

Never use machine torque to make or break joints away from the machine. To break threaded joints away from the machine, first shut down the engine and then use a breakout wrench to perform the task. Clamp onto the drill pipe only in the designated areas; even small cuts in the pipe can quickly lead to fatigue during bending rotation. With a Ditch Witch EZ Connect tool, you don't have to break apart tight threads on downhole tools.

During the drill operation, never rotate the drill pipe without pushing or pulling, as this will increase stress damage at every bend. Likewise, don't push a full length of pipe in the drill frame without rotating, as this can cause pipe to buckle. Drill in half the pipe before pushing without rotation.

When guiding the bore, never exceed the bend radius for your pipe. Bending pipe more sharply than recommended will damage the pipe and cause failure. All steering corrections should be made as gradually as possible. Overcorrecting will cause "snaking," which can damage pipe and make drilling and pullback more difficult. It is important to begin straightening out of each correction as early as possible.

Excessive changes in pitch—the up or down angle of the bit and lead pipe—can bend the pipe just like oversteering does. In your operator's manual, the bend limits for Ditch Witch pipe are shown in a chart that provides the total deflection allowable in pitch or steering without damaging the pipe.

Because each pipe comes in contact with the saver sub, check it regularly for wear and replace it when it is worn, or it will damage the drill pipe. And always replace bits and backreamers as soon as they become worn, because dull tools put more strain on the drill string.

During Pullback.

Stresses on the product during pullback are transferred to the backreamer and drill pipe. When pulling in the product, be advised of the following:

• Do not pull the backreamer faster than it can cut.    
• Never backream without good fluid flow. The right mixture and flow reduce torque, thrust and pullback forces.
•  Use the smallest backreamer practical for pullback. If you need a large borehole, make more than one pass, each with a progressively larger reamer.

After The Bore.

When buying replacement pipe, always replace the entire string with pipe from the same manufacturer. The HDD industry has no established industry standard for threads, so not all threads are made equally. Parts from different manufacturers may appear to assemble, but this does not mean the joint was made up correctly.

Thread tolerances vary widely among manufacturers. And worn threads, of course, do not match any other threads. Mixing new and worn threads increases contact pressure and accelerates thread wear. Also, the bend radii of different brands of pipe may be different, which will cause accelerated and uneven wear on all pipe in the string.

Whenever you replace all of your drill pipe, replace the saver sub on the carriage, too. Putting new pipe through an old saver sub transfers damage from the sub to every new pipe in the string.

Because the lead drill pipe is in the ground longer, it is subjected to higher shock loads and experiences more wear. To help spread this wear evenly over all pipe, move the lead pipe to the last position in the rack after each job.

Drill Pipe Best Practices.

By making every effort to maximize the life of your drill pipe, you can help ensure the overall success of your HDD operations. Here's an abbreviated checklist to refer to when planning your next bore:

• Set up unit correctly. 
• Securely anchor drilling unit.    
• Break in threads on new pipe.    
• Make up and break out tool joints correctly.    
• Assemble and disassemble tool joints at moderate speed.    
• Keep the rotation speed and thrust speed synchronized. 
• Apply proper torque to all tool joints.    
• Avoid over-bending, over-steering and over-correcting.    
• Keep threads clean and lubricated.    
• Use correct drilling fluid for soil conditions and use plenty of it.    
• Refer to your operator's manual for complete drill pipe care, maintenance and operation.