Shank Adapters

Shank Adapters: The Critical Link Between Rock Drill and Drill String

MSD (Zhuzhou Jingde Machinery Co., Ltd.) is a China-based rock drilling tools manufacturer with 23+ years of experience. We produce aftermarket replacement shank adapters compatible with all major rock drill brands, including Epiroc / Atlas Copco, Sandvik, Furukawa, Montabert, Ingersoll Rand, and Krupp.

What Is a Shank Adapter?

A shank adapter is the connecting component between the rock drill and the drill string. It serves three critical functions:

Energy transfer — The spline end (impact end) receives millions of high-frequency percussion blows from the rock drill piston and transmits this energy to the drill rod.

Rotation transmission — The adapter transfers rotation torque from the drill's rotation motor to the threaded drill string.

Flushing channel — The center bore allows compressed air or water to flow through the entire drill string, clearing rock cuttings from the hole bottom.

Because the shank adapter absorbs the full impact energy before any other component, it experiences the highest stress concentration in the entire top hammer system. A worn or cracked shank adapter causes energy loss, drilling deviation, and accelerated wear on both the rock drill chuck and the drill rods.

Rule of Thumb: Never mix an old, severely worn shank adapter with a brand new drill rod, or vice versa. The worn threads will rapidly destroy the new ones, costing you significantly more in premature tool failure.

Shank Adapter Anatomy and Wear Patterns

Understanding the key components helps diagnose wear and select the correct replacement:

Spline (Impact End) — The spline engages with the rock drill's chuck and receives direct piston impact. This end experiences the most severe wear. Signs of failure include mushrooming (flattening of spline tips), cracking, and spalling. MSD shank adapters feature deep-case carburizing (1.5–2.0 mm case depth) to maximize spline life.

Thread End — The threaded portion connects to the first drill rod or coupling sleeve. Thread wear appears as rounded crests, surface pitting, or galling. MSD uses precision CNC threading to ensure tight tolerance fit with standard R32, R38, T38, T45, T51, and ST58 threads.

Center Flushing Hole — The bore diameter must match system requirements for adequate flushing velocity. A rough or corroded bore increases pressure drop and reduces cuttings evacuation efficiency.

Body — The main body transfers rotation torque and absorbs vibration. MSD applies controlled heat treatment to achieve 58–62 HRC surface hardness while maintaining 28–32 HRC core toughness — the optimal balance for impact resistance and fatigue life.

Thread Type Selection Guide

Selecting the correct thread type is essential for system compatibility and performance:

R32 / R38 — Smaller threads for light to medium rock drills. Typical bit diameter range: 38–64 mm. Common in development drilling, rock bolting, and small tunneling jumbos.

T38 — The most widely used thread in surface drilling. Covers bit diameters from 51–76 mm. Compatible with the majority of production rock drills worldwide. If uncertain, T38 is usually the safe choice for general quarry and mining bench drilling.

T45 — Heavy-duty thread for larger production drills. Bit diameter range: 64–89 mm. Preferred for deep bench holes and high-penetration applications.

T51 — The standard for large-scale production drilling. Bit diameter range: 76–115 mm. Required when drilling deep holes (>20 m) or using large-diameter button bits.

ST58 / MG60 / MT60 — Specialized threads for long-hole drilling, sublevel stoping, and raise boring applications. Bit diameters exceeding 102 mm.

Rule of Thumb: Never mix thread types in a drill string. A T38 shank adapter must connect to T38 rods and T38 bits. Mismatched threads cause joint failure and potential downhole loss.

MSD Manufacturing Process

MSD shank adapters are manufactured using the same processes as OEM suppliers, ensuring drop-in replacement compatibility:

Material Selection — We use premium alloy steel grades specifically formulated for high-impact rock drilling applications. Chemical composition is verified by spectrometer analysis for every heat lot.

Precision Forging — Near-net-shape forging produces optimal grain flow along the adapter's stress axis, maximizing fatigue resistance.

Deep-Case Carburizing — The spline end undergoes controlled carburizing at 920–940°C for 8–12 hours, achieving 1.5–2.0 mm case depth with 58–62 HRC surface hardness. This process hardens the impact surface while preserving core toughness.

CNC Thread Machining — Thread profiles are cut on multi-axis CNC lathes with in-process gauging to maintain API-standard tolerances.

Heat Treatment — The complete adapter undergoes quenching and tempering to achieve the specified hardness gradient from surface to core.

Quality Verification — Every production batch undergoes dimensional inspection, Rockwell hardness testing, magnetic particle inspection for cracks, and thread gauge verification.

Compatibility and Replacement

MSD shank adapters are designed as direct replacements for original equipment parts. We manufacture adapters compatible with:

Epiroc / Atlas Copco — COP 1036, 1038, 1132, 1238, 1432, 1532, 1440, 1550, 1638, 1838 (all variants), 1840 HE, 1850, 2150, 2160 EX, 2238, 2540 EX, 2550 UX, 2560 EX, 3060 MEX, 4050

Sandvik — HL 300–1560 T series, HLR 438 series, HLX 5, HFX 5, RDX 5, L 400–550, RD 308–525

Furukawa — PD 200 series, HD 300–828 RP series

Montabert — H 100, HC 25–200 A series

Ingersoll Rand — URD 475/550, EVL series, VL series, YH 45–100 series, Hydrastar 200

Krupp — HB 32, HB 101

When ordering replacement shank adapters, provide your rock drill model and current thread type. MSD engineers will confirm the correct part number and dimensions before production.

MSD manufactures aftermarket replacement parts. Brand names are referenced solely to indicate compatibility. MSD is not affiliated with, endorsed by, or an authorized dealer of any listed original equipment manufacturer.

Proven Field Performance

Australian Iron Ore Mine (Epiroc / Atlas Copco COP 1838 Replacement): A Pilbara mining contractor replaced OEM shank adapters with MSD T38-525 mm adapters on their Epiroc COP 1838 fleet. Over a 12-month tracking period, MSD adapters achieved equivalent service life at 40% lower procurement cost. Zero premature spline failures were recorded.

Why Choose MSD Shank Adapters

OEM-Equivalent Quality — Same materials, same processes, same tolerances as original equipment suppliers. Direct drop-in replacement guaranteed.

Full Thread Range — R28, R32, R38, T38, T45, T51, ST58, MG60, MT60 in stock for immediate shipment.

Complete Brand Coverage — Compatible replacements for Epiroc / Atlas Copco, Sandvik, Furukawa, Montabert, Ingersoll Rand, and Krupp rock drills.

Carburized Spline Technology — Deep-case carburizing delivers superior impact end life in hard rock conditions.

ISO 9001 Certified — Full traceability from raw material to finished product.

Trusted by 500+ Drilling Contractors — MSD shank adapters are operating in 40+ countries across mining, quarrying, tunneling, and construction applications.

Technical content reviewed by MSD Engineering Team. | About MSD: Zhuzhou Jingde Machinery Co., Ltd. — 23+ years of rock drilling tools manufacturing expertise | ISO 9001 Certified | Serving 500+ contractors in 40+ countries