Boart Longyear

From percussive rods and API rods to extension rods, Boart Longyear^TM offers a variety of rods designed for specific drilling applications. A variety of diameters and thread types are also offered on each of our rods for a maximum compatibility.

Rotary Percussive Rods Friction Welded - TDN

TDN drill rods are designed for use on the inner drill string of Duplex and rotary-percussive drilling systems. TDN rods are an alternate to the T3 and T45 extension rods used in these systems. Up-hole flushing velocity may be reduced when using T38 and T45 rods due to the large annulus.
TDN systems are designed to minimize the area between the inner rod and casing so that up-hole flushing velocity is optimized. The bigger inner diameter of the inner rod allows a higher flushing medium flow without creating back-pressure. In addition to improved flushing, TDN systems also utilize the patented TwinDrive rotary percussive thread and the highest grade thread steel to provide longer rod life.

Friction welded rods have quenched and tempered pin and box ends constructed of high tensile strength steel. The threaded ends are friction welded onto a mid-body manufactured from annealed mid-grade steel.

API Drill Rods

API DTH drill rods are designed for use in rotary and rotary DT applications. These are commonly used as single rotary rods or as the inner drill string on double head rotary-rotary applications.
The rod ends of our API rods are constructed of high tensile strength quench and tempered steel. The rod ends are gas nitrated to provide additional life to the drill string. Rod ends are friction welded onto mi grade mid-body material.

API rods are manufactured in a variety of lengths and wall thickness and include IF designs for additional flushing capacity. Boart Longyear can manufacture alternative rod lengths and spanner flats upon request.

Extension Rods T38/T45

T38 and T45 extension drill rods are designed for use as the inner drill rod extension for double head rotary percussive drilling systems. The extension drill rod is designed with male threads on both ends with a coupling connection between them.

The T38 and T45 thread profiles are specially designed to withstand the percussive forces exerted on the inner drill string by the hydraulic drifter.

The outer diameter of the extension drill steel is relatively small compared to the inner diameter of the casing. This can cause the inner drill string to have movement within the casing. To reduce this movement, Boart Longyear also offers couplings with centralizing guides to keep the rods on center in the casing.

TDN drill rods are an alternative for T38 and T45 drill steel and feature improved flushing capacities and decreased tolerances between the inside diameter of the casing.