Starter guide tubes — also called guide rods — are the first rod in a top-hammer drill string on rigs that run a guide-tube system: a heavy-wall round tube with a male thread at the bit end and a female thread at the drill end that couples straight onto the shank adapter, with no coupling sleeve. The large outside diameter nearly fills the hole, so it steers the string straight through the collar and the first few feet where deviation starts, then standard male/female extension rods carry the hole to depth.

Crowder Supply offers guide tubes in R32, T38, T45, T51, ST58 and GT60 threads on 1-3/4 in. through 3-3/8 in. round tube, in lengths from 39 in. to 204 in., plus 2-3/8 in. round GT60 guide rods. Pick the thread to match your shank adapter and extension rods, the tube OD to match your bit and hole size, and the length. The guide to choosing drill steel and rock drill bits covers matching thread, section and length to your drifter and ground.

• End configuration: male bit-end thread, female rod-end thread — couples direct to the shank adapter
• Threads: R32, T38, T45, T51, ST58 and GT60
• Tube OD: 1-3/4, 2-1/4, 2-1/2, 3 and 3-3/8 in. round; 2-3/8 in. round guide rods (GT60)
• Lengths from 39 in. (1 m) through 204 in. (17 ft)
• Heavy-wall alloy steel tube, heat-treated, with precision-machined threads for straight-hole collaring and efficient energy transfer
• Applications: bench and production drilling, long-hole and surface top-hammer rigs where hole straightness matters
• Brands: Brunner & Lay, Rockmore, Mitsubishi, Sandvik and Epiroc; quoted per size, ships from Denver