Product Description
At RockHound, we engineer every product for one purpose: to keep your drill string running longer, straighter, and harder — without compromise. Our T45 Extension Round Rods are the backbone of high-performance long-hole drilling systems, purpose-built for underground mining and surface quarrying in medium-to-hard rock formations.
Each rod is forged from ZK22CrNi3Mo (23CrNiMo) low-alloy case-hardening steel — a material specification chosen for its exceptional fatigue strength and impact toughness — then precision CNC-machined and subjected to full-surface carburization heat treatment. The result is a rod with a wear-resistant outer case and a resilient, energy-absorbing core: exactly what deep, sustained percussive drilling demands.
From sublevel stoping to bench drilling to tunneling, RockHound T45 rods are engineered to reduce hole deviation, extend thread service life, and maximize energy transmission from rig to bit — cycle after cycle, shift after shift.
Key Features
ZK22CrNi3Mo (23CrNiMo) Alloy Steel
Every RockHound rod begins with mill-certified ZK22CrNi3Mo (23CrNiMo) low-alloy case-hardening steel, selected for its high impact toughness, superior fatigue strength, and reliable performance in abrasive and fractured rock environments — minimizing the risk of down-hole breakage.
Full-Surface Carburization Heat Treatment
RockHound’s full-surface carburization process produces a high-hardness, wear-resistant case while preserving a ductile, tough core — a dual-property structure critical for absorbing continuous percussive stress without premature cracking or deformation.
CNC-Machined T45 Precision Threads
Threaded ends are machined to exacting tolerances on RockHound’s CNC production lines, ensuring consistent metal-to-metal contact at every rod-sleeve-bit interface. Tight thread engagement minimizes energy loss during percussion and reduces joint loosening under dynamic load.
High Straightness Tolerance
Strict dimensional control throughout RockHound’s manufacturing process limits rod bow to the tightest industry tolerances — critical for maintaining hole accuracy in deep-hole applications and extending guide tube service life.
Optimized Flushing Groove Design
RockHound’s engineered flushing channels facilitate efficient drill cuttings removal and bit cooling, reducing regrip friction and preventing bit balling in fine or clay-bound formations.
RockHound T45 (1 3/4″) long-hole drilling string: Shank Adapter → Coupling Sleeve → Extension Rod / MF Rod → Guide Tube → Coupling Sleeve → Ballistic Button Bit / Button Bit / Retrac Bit.
Technical Specifications
| Model | Length (mm) | Length (ft) | Diameter (mm) | Diameter (in) | Thread | Product Code | Weight (kg) |
|---|---|---|---|---|---|---|---|
| T45-Round 46-T45 | 1525 | 5′ | 46 | 1 3/4″ | T45 | 280-4615-7777 | 16.2 |
| T45-Round 46-T45 | 1838 | 6′ | 46 | 1 3/4″ | T45 | 280-4618-7777 | 19.5 |
- Brand: RockHound
- Material: ZK22CrNi3Mo (23CrNiMo) low-alloy case-hardening steel
- Body Profile: Round, 46mm (1 3/4″)
- Thread Standard: T45 (both ends)
- Heat Treatment: Full-surface carburization + quench & temper
- Surface Finish: Anti-rust coating / phosphating (standard)
Applications
RockHound T45 Extension Round Rods are the field-proven choice for long-hole drilling systems requiring high penetration rates, minimal hole deviation, and reliable service life under sustained impact loading:
- Sublevel Stoping (Underground Mining): The primary application. RockHound T45 46mm rods are widely specified for long-hole production drilling in sublevel and bench-and-fill stoping operations in metalliferous mines.
- Surface Bench Drilling: High-throughput aggregate quarrying and open-pit mining where consistent hole straightness and rapid rod exchange are critical.
- Tunneling & Development Heading: Used in fan drilling and reinforcement bolting where extended rod string depth is required.
- Grouting & Ground Support: Applicable for long-distance grouting hole drilling in civil and geotechnical projects.
- Rig Compatibility: RockHound T45 rods are fully interchangeable with T45-standard systems from Atlas Copco (Epiroc), Sandvik, Furukawa, and other major hydraulic rock drill manufacturers.
Maintenance & Care
RockHound recommends the following field maintenance procedures to maximize the service life of your T45 Extension Round Rods and protect adjacent string components:
- Thread Lubrication Before Every Coupling Apply purpose-formulated rock drill thread grease to both male T45 threads before each assembly. This is the single most impactful maintenance action — preventing galling, seizing, and micro-welding under high-torque impact conditions, which remains the primary cause of premature T45 thread failure in the field.
- Rotate Rod Leading End Periodically Swap the leading (drill-end) and trailing (rig-end) at regular intervals to distribute thread wear evenly across both T45 joints. RockHound field data shows this practice can extend total rod life by up to 30%.
- Never Run Blank (No-Load) Firing Operating the hammer at full percussion without rock contact sends unrestricted shock waves through the rod body, concentrating fatigue stress at thread roots and flush holes. RockHound strongly advises enforcing a strict no blank-firing policy on site.
- Inspect Thread Profiles at Each Shift Check for flank wear, flattening, or chipping using a thread gauge or visual inspection. Retire RockHound rods at the specified wear limit to prevent cascading damage to coupling sleeves and shank adapters.
- Storage & Handling Store RockHound rods horizontally on proper steel racking to prevent long-term bowing. Keep thread protectors fitted during transit and storage. Avoid ground contact and prolonged exposure to moisture.
How to Choose the Right RockHound Extension Rod
Before specifying RockHound T45 Extension Round Rods for your operation, evaluate the following:
- Drilling Depth & String Configuration For hole depths exceeding 30–40m, integrate a RockHound Guide Tube in the string to maintain hole straightness. For faster rod handling and fewer connection points, consider RockHound MF (Male-Female) Rods as an alternative to the standard coupled rod + sleeve configuration.
- Rock Hardness & Abrasivity RockHound’s ZK22CrNi3Mo (23CrNiMo) specification delivers an optimal balance of surface hardness and core toughness for medium-to-hard rock (UCS 80–200 MPa). For formations with extreme abrasivity (e.g., quartzite, granite >200 MPa), contact RockHound’s technical team to confirm the appropriate heat treatment specification.
- Rig Percussion Energy RockHound 46mm round rods are rated for medium-to-high-power hydraulic drifters. Verify that your rig’s percussion energy and feed pressure fall within the operating range recommended for 46mm rods to prevent bending or fatigue under off-axis loading.
- Thread System Compatibility Confirm T45 thread compatibility across all string components (bit, coupling sleeve, shank adapter). Do not mix T38 and T45 components — RockHound advises that thread geometry mismatch is among the most common causes of rapid joint failure in mixed-inventory operations.
- Length Selection Choose the RockHound 1525mm (5′) rod for tighter headings with restricted breakout clearance, or the 1838mm (6′) rod for standard long-hole production drilling where maximizing advance per cycle is the priority.
Why Choose RockHound
- Mill-Direct Supply Chain: RockHound sources ZK22CrNi3Mo billets directly from qualified steel mills, with full material traceability and heat batch documentation available on request.
- In-Process Ultrasonic Flaw Detection: Every RockHound rod undergoes ultrasonic flaw detection before final machining — zero tolerance for internal defects.
- OEM-Compatible Thread Gauging: All RockHound T45 threads are verified against Atlas Copco / Epiroc and Sandvik gauges to guarantee full interchangeability with your existing equipment.
- Flexible MOQ & Responsive Lead Times: RockHound supports both trial procurement and standing supply agreements, with fast global logistics to active mine sites.
Related Production
The T45 threaded button drill bit is a high-strength drilling tool commonly used for hard rock drilling, and is used in conjunction with T45 threaded coupling sleeve. Its diameter typically ranges from 76mm to 89mm, and common designs include flat-faced and Retrac (retractable) types.The button head can be designed with spherical or parabolic teeth to improve drilling efficiency and wear resistance.
This drill bit is widely used in tunnel excavation, large open-pit mines, and underground copper and gold mines, and is characterized by its fast drilling speed, long service life, and stable performance.
FAQ — RockHound T45 Extension Round Rod
RockHound T45 Extension Round Rods are manufactured from ZK22CrNi3Mo (23CrNiMo), a premium low-alloy case-hardening steel recognized in the rock drilling industry for its high fatigue strength, impact toughness, and resistance to down-hole fracture. All billets are sourced from certified mills with full material traceability.
RockHound currently offers the T45-Round 46-T45 rod in two standard lengths:
- 1525mm (5′) — Product Code: 280-4615-7777 | Weight: 16.2 kg
- 1838mm (6′) — Product Code: 280-4618-7777 | Weight: 19.5 kg
Both variants feature a 46mm (1 3/4″) round body with T45 threads on both ends. Contact RockHound for custom length availability.
Yes. RockHound T45 Extension Round Rods are machined to T45 thread standard and fully compatible with T45-spec equipment from Atlas Copco (Epiroc), Sandvik, Furukawa, and other major hydraulic rock drill manufacturers. All thread profiles are verified against OEM gauges before shipment.
A standard Extension Rod uses identical T45 male threads at both ends and requires a separate Coupling Sleeve to connect rods in a string. An MF (Male-Female) Rod integrates both thread genders into a single piece, eliminating one coupling sleeve per connection. RockHound MF Rods reduce the number of joints in long strings, speeding up rod handling and lowering the risk of coupling sleeve failure in deep-hole applications.
Carburization is a case-hardening heat treatment process in which carbon is diffused into the surface layer of the steel at elevated temperature. RockHound applies full-surface carburization to all T45 Extension Rods, creating a hard, wear-resistant outer case (ideal for thread longevity and abrasion resistance) while maintaining a tough, ductile core (critical for absorbing percussive shock without brittle fracture). This dual-property structure is what differentiates a quality drill rod from a generic one.
The three highest-impact practices are:
- Grease threads before every coupling — prevents galling and thread seizure.
- Rotate the leading end periodically — equalizes wear across both T45 joints.
- Eliminate blank firing — unrestricted percussion without rock contact is the leading cause of premature fatigue fracture in all extension rods, including RockHound products.
Full maintenance guidelines are available in the RockHound T45 Maintenance & Care section above.
For holes deeper than approximately 30–40m, RockHound strongly recommends incorporating a Guide Tube in the drill string. The guide tube stabilizes the leading end of the string, constrains lateral movement, and significantly reduces hole deviation — protecting your RockHound rods, bits, and collars from off-axis stress that accelerates wear and can cause string deflection or stuck rod incidents.
RockHound offers flexible procurement options to suit operations of all scales — from initial trial orders to long-term standing supply agreements. Please contact our sales team with your project specifications (hole depth, rig model, monthly consumption estimate) for a tailored quote and lead time confirmation.