In top hammer rock drilling, a MF rod (also known as a speed rod or male-female rod) is a specialized drill rod designed for quick and efficient rod changing to minimize downtime during drilling.

What is an MF Rod?

It's a hollow, high-strength steel rod with male threads on one end (external) and female threads on the other end (internal). It is designed for rapid coupling with other rods or the drill bit. Typically shorter than standard extension rods, optimized for fast feed systems.

What is it Used For?

1.Faster Rod Changes – Reduces time spent adding/removing rods compared to traditional male-male (MM) rods.

2.Efficient Drill String Assembly – Simplifies connections since each rod automatically mates with the next.

3.Improved Flushing – Maintains smooth airflow/water passage for better hole cleaning.

4.Compatibility with Auto-Handlers – Often used in automated drilling rigs for seamless rod handling.

Main thread sizes for drifter rods: R25, R28, R32, R38, T38, T45, T51 (male-male)

Main steel shape and size: round 32mm, 38mm, 45mm, 51mm

Material: 23CrNi3Mo

Processing technology: Carburized

Typical Applications

Surface mining & quarrying (high-speed blast hole drilling).

Tunneling & construction (where rapid advance is critical).

Automated drill rigs (robotic rod handlers prefer MF threading).