Male/female extension rods from Crowder Supply stack directly rod to rod with no coupling, across the common top hammer thread systems: R25, R32, R38, T38, T45, T51, ST58 and GT60. Rods run from 24 in. to 246 in. on hex and round bar stock from 1 in. to 2-1/2 in., for extension drilling in mining, tunneling, tiebacks, geotechnical work and construction blast-hole drilling.

A male/female string builds joint by joint: shank adapter to rod, rod to rod, rod to rock drill bit, and every joint wants the same thread system and bar size. The female end threads straight onto the next rod’s male end, so there is no coupling to buy, lose or strip. For male/male rods used with couplings, see the male/male extension rods. Crowder Supply stocks rods from Brunner & Lay, Mitsubishi, Rockmore, Sandvik and Epiroc, and the guide to choosing drill steel and rock drill bits covers matching steel to your drill and ground conditions.

• Thread systems: R25, R32, R38, T38, T45, T51, ST58 and GT60 rope, trapezoidal and speed-rod profiles
• Lengths from 24 in. through 246 in. (nominal) to build any practical string depth
• Male/female ends for direct rod-to-rod stacking, no coupling required
• Bar stock: 1 in., 1-1/4 in., 1-3/8 in. and 1-1/2 in. hex; 1-1/4 in. to 2-1/2 in. round
• Brands stocked: Brunner & Lay, Mitsubishi, Rockmore, Sandvik and Epiroc
• Applications: extension and production drilling, tiebacks, geotechnical, oil & gas and environmental drilling
• Stocked by Crowder Supply in Denver in the popular sizes