Typically, manufacturing sonic drill rods is a three-piece construction process in which the rod ends are friction- or slip-fit and welded onto a mid-body. This allows manufacturers to use lower grades of steel in the mid-body to save on costs.

Boart Longyear utilizes an upset forging process in manufacturing its sonic drill rods. Upset forging refers to the process in which a drill rod begins its life as one single piece of high-grade steel tubing and is internally forged to ½” thickness on the thread ends which transitions to ¼” mid-body wall thickness. This eliminates welding the thread ends onto the mid-body, creating a significantly stronger one-piece-design sonic drill rod. 

At a high-level, the six manufacturing steps for sonic drill rods are:

1. Begin with high-grade steel tubing having 3 ½” outer diameter and ¼” wall thickness
2. Upset forge the rod ends to 9” in length and ½” wall thickness
3. Stress relieve the entire rod (heat and cool slowly)
4. Heat treat the rod pin and box ends (quench and temper) for strength and durability
5. Machine the pin and box tapered threads into the upset forged ends
6. Heat treat the pin thread a second time to a slightly higher hardness (increases life, prevents galling (rods seizing up into each other during drilling) and increases wear resistance)

This process, which draws on our vast experience manufacturing diamond coring rod, creates a 3 ½” outer diameter rod which has a 3” inner diameter mid-body and 2 ½” inner diameter thread ends. The rod ends are ½” wall thickness to 9” in length, while the mid-body is ¼” wall thickness, keeping the rod relatively light but extremely durable.

When you need the best and most efficient sonic tooling, look no further than Boart Longyear. High-quality precision steel plus special heat treatment processes provide unsurpassed stability, straightness, and durability of the sonic drill string assembly. Stringent manufacturing standards and ISO certification make sonic tooling from Boart Longyear the right choice for every sonic drilling project.

Contact your local Boart Longyear representative or distributor today.

Quality Policy:

Boart Longyear is committed to providing quality products, innovative solutions, exceptional service and value to our customers while meeting or exceeding all customers’ safety, environmental and regulatory requirements.