#

Hard Rock Performance Tooling

Boart Longyear designs and manufactures the most technologically advanced drilling products in the industry, and our legacy of innovation and expertise is evident in our extensive percussive tool offering. From handheld drill steels and bits, to a complete selection of rods, couplings and adaptors, we provide complete solutions for any percussive/drill and blast application.

  • Hand-held (short hole) System overview – Ideal for short hole drill & blast, as well as roof bolting applications, our hand-held system is comprised of premium alloy tapered hexagonal drill steels ranging from 0.5 m up to 7.9 m in length, and complimented by a complete range of reamers, blade and button bits.
  • Production Mining System overview - The Boart Longyear production system for mine development and log hole drill & blast applications includes a threaded shank adapter, couplings, both round and hexagonal extension drill steels—male/male and male/female—and a range of button, blade and retrac bits.
  • Tunneling/Ground Support overview – Our tunneling and ground support system consists of a threaded shank adapter, couplings, both round and hexagonal drill steels, a threaded pilot adapter/reamer, and a range of both threaded and tapered button and blade type bits.

Featured Hard Rock Performance Tooling

Based on application, Boart Longyear utilizes 2 different types of heat treatment on our percussive drill string components to maximize performance and reliability.

Carburization - Used primarily in underground applications where water is used as a flushing medium, in this process the entire rod is hardened, providing a case over the entire rod surface both internally and externally.

High Frequency (H/F) Induction – For surface drilling applications where air is the primary flushing medium, a high frequency induction method is used to harden only the threads of the rod.

Round vs. Hex

  • Round Rods – Generally more lightweight than hexagonal rods, round rods are typically used in long hole extension drilling applications.
    • Normally used in extension drilling applications
    • Generally lighter than hexagonal rods of an equivalent size
    • Available in large x-sectional diameters
    • Diameter of rod is based off external dimension
  • Hexagon Rods – Hexagonal rods are more rigid, and transfer energy more efficiently than round rods, making then perfect for short hole applications there accuracy is critical.
    • The cross sectional dimension of material is measured across the flat
    • Cross sections are more rigid, heavier & transfer energy more efficiently
    • Reduces the annulus in the drill hole for better flushing
    • Smaller space combined with the corners of the steel create turbulence in the hole
    • keeps the heavier cuttings moving, especially with horizontal holes
    • The rigidity of the cross section makes it possible to use a larger thread
  • Handheld (short hole) Steel – This design provides a hexagonal chuck section to provide leverage for the rotation chuck bushing. It features a forged collar to maintain the proper shank striking face position in the rock drill, and a tapered bit end. Tapered steel lengths—available from 0.6 m to 3.6 m in length—are measured from the collar to the bit end. Holes are typically drilled in 0.6 m increments to accommodate the airleg feed length. The drilled steel is then extracted and followed with a slightly smaller diameter bit on the next steel length in the sequence.
  • Extension Steel – With the longer steel tending to be larger in diameter, conventional extension steel is characterized by a duplicate thread on each end of the steel. Hexagonal and round cross sections are available, though round cross sections are more prevalent.
  • Tunneling Steel – It is common practice to bump up the drive end of drifting steel for added strength at the rock drill end to accommodate larger diameter and shank adapters. Drill steel is available in many standard lengths to match the drill feeds on a multitude of available drifting jumbos.
  • Male/Female (m/f) Steel – An alternative to the use of couplings is to include the female part of the threaded connection as an integral part of the drill steel. Male/Female drill steel provides more rigid connections and is easier to uncouple and handle. The service life also tends to be better than with separate couplings. The advantages of drilling with M/F steel include: easy handling, quicker uncoupling, tighter connections and the potential to drill straighter holes.

Threads

Boart Longyear offers percussive rods with a variety of thread profiles—rope, HM, EL, and BE—each with their own unique characteristics and specialization.

  • Rope thread
    • Rope threads have a low pitch, 12.7 mm and a small angle of profile
    • Sizes: 22 mm – 38 mm
    • Good wear properties but poor uncoupling capability
    • Ideal for single pass or short hole drilling such as underground tunneling applications that require infrequent uncoupling
    • Rope thread larger than R32 is not recommended for extension drilling, especially with high powered drills that have high rotational torque as they will be difficult to uncouple
  • HM thread
    • HM thread or “T” thread has a larger pitch and a larger angle of profile than the Rope thread
    • Sizes 38 mm, 45 mm and 51 mm
    • Excellent wear properties and good coupling qualities
    • It is ideal for extension drilling with multiple steel
    • Compatible with heavy high torque rock drills for surface and underground applications
  • EL thread
    • Similar angle of profile to the HM thread
    • Designed for a 60 mm and 70 mm diameter extension steel for use with the new generation high powered rock drills
    • Excellent wear resistance and a pitch angle that uncouples easily
    • Vital component of the LASEROD® Straight Hole Drilling System
  • BE thread
    • Thread is a shoulder drive system (available in bottom drive as well). The shoulders on the pin and box butt together to transmit energy
    • Excellent wear properties and good coupling qualities
    • This thread is used in extension tube drilling with multiple tube steels
    • Compatible with high torque top hammer rock drills for surface and underground applications

Semi-bridge coupling

  • Small non-threaded bridge in the center
  • Steel cannot thread past bridge area
  • Smaller diameter steel end portions fit together in the centre bridge area of the coupling
  • Semi-bridged couplings are most suited to high torque machines

Adapter Coupling

  • Used when changing from one thread type, or size, to another and are typically required only in special circumstances

Hydraulic & Pneumatic Shanks – Male shank adapters are ideal for drifting, tunneling & extension applications where high bending stresses are present, and female shank adapters are used in underground bolting applications, or other situations when the drilling space is limited.

Boart Longyear offers both internal and external flushing options. Internal flushing uses a water tube that fits through the center of the drill and into an o-ring seal in the end of the shank to transfer flushing into the drill string.

For external flushing, holes or a slot are required in the side of the shank adapter. These line up between seals inside the front head or water box of the rock drill when the shank is installed. Flushing medium is supplied directly to this device and is introduced into the drill string through the shank.

The shanks for hydraulic drills and some pneumatic drills have external or front head flushing. Hydraulic shanks generally have at least a 5 to 14-spline configuration, and pneumatic shanks tend to have internal or through-

Boart Longyear offers 2 types of percussive bits: button-type and blade-type.

Button bits are a moderately abrasive type of bit used where fast penetration is required, and straightness is less critical. Ideal for medium to hard ground, these bits are recognized by their characteristic raised buttons and grooved chipways and flushing holes on the face.

Blade bits are used when a straight hole is critical. While these bits penetrate slower than a button bit, they maintain accuracy and hole diameter with reduced gauge wear, as compared to button bits. This type of bit is recognized by its sharp, raised “X” pattern and centered flushing hole on the face.

For large diameter service holes for drainage, electrical cable, or pipelines where pilot holes are required, Boart Longyear offers 2 types of reaming bits: button bit reamers and pilot adapter/reamers.

Button bit reamers are a one-piece bit with an integrated pilot on the face. The pilot adapter/reamer is a two-piece system, comprised of a 6° tapered pilot adapter that threads onto the lead steel with a taper socket reaming bit fitted on the pilot, typically used in handheld applications.

Button Bits

  • Components - Button bits are categorized by a variety of criteria: bit diameter, skirt length, skirt diameter, wall thickness, and gauge clearance angle, face design, and button insert types.
  • Skirt Designs intro - Our button bit skirt designs can be split into two categories: Retrac and Straightrac.The Retrac skirt features an extended body, with cutting edges or ribs designed into the skirt. This design ensures easy removal and completion of the bit in adverse ground conditions.The Straightrac skirt features an angled flute design with an extended skirt body that maintains 360° contact in the hole. The Straightrac design has been field tested and proven to provide straight holes in even the most adverse ground conditions.
  • Face design -
    • BR - Button Recessed – Ideal for straight hole applications in broken ground, button recessed bits are characterized by a unique “drop center” face design.
    • BF - Button Flat – Defined by their flat face design, these general purpose bits are designed to be effective in medium to hard ground conditions.
    • BC - Button Chisel – With a distinct chisel shape, this fast-penetrating style of bit is perfect for abrasive conditions, and is often utilized in tunneling applications.
    • BD - Button Dome – Featuring a clearly defined raised profile, this style of bit is used primarily in reaming applications in soft ground.
  • Insert type
    • Hemispherical Button - (Height 0.5 Ø)
      • Application Strength - multipurpose
      • Best suited to hard ground
      • 25,000 to 45,000 PSI (170 to 300 MPa)
      • Abrasive to very abrasive
    • Ballistic Button - (Height 0.75 Ø)
      • Application Strength - fast penetration
      • Best suited to soft ground
      • 10,000 to 20,000 PSI (70 to 140 MPa)
      • Non abrasive ground
    • Parabolic Button (semi ballistic) - (Height 0.6 Ø)
      • Application Strength - fast penetration
      • Best suited to medium ground
      • 15,000 to 25,000 PSI (100 to 170 MPa)
      • Mildly abrasive ground
    • Conical Button - (Height 0.65 Ø)
      • Application Strength – fast penetration
      • Suited for all non-abrasive ground types
      • Smaller contact area
      • Best suited for smaller diameter bits
  • Number of buttons – (charts in catalog)
    • 33 mm - 45 mm - 3 - 6 buttons
    • 45 mm - 51 mm - 4 - 6 buttons
    • 51+ mm - 6 - 10 buttons
    • Hard Rock - Larger Ø
    • Medium Rock - Smaller Ø
    • Soft Rock - Smaller Ø

Blade Bits

Blade bit designs feature both cross and “X” type face configurations. 32 mm to 57 mm diameter bits are restricted to a cross configuration, and 57 mm or larger diameter bits usually have an ‘X’ configuration.

Where accuracy is required in very hard, abrasive ground, blade bits are ideal, as they tend to resist gauge wear better than button bits. However, blade bits are not as productive and yield higher drilling costs than button bits. In addition, blade bits generally require more frequent sharpening than button bits because of the less wear resistant carbide grades on the face.

Reaming Bits

For large diameter service holes for drainage, electrical cable, or pipelines where pilot holes are required, Boart Longyear offers 2 types of reaming bits: button bit reamers and pilot adapter/reamers.

Button bit reamers are a one-piece bit with an integrated pilot on the face. The pilot adapter/reamer is a two-piece system, comprised of a 6°

tapered pilot adapter that threads onto the lead steel with a taper socket reaming bit fitted on the pilot.

  • Bit Adapter

    • Conversion from thread to thread
  • Gauge Taper
    • Tapered tool for checking dimensions
  • Guide Adapter
    • Stabilize drill string
    • Helps reduce hole deviation
    • Bell Tap Tool for retrieval of rods
    • Fits over OD of rod Driver Dolly
    • Used for roof bolting applications
  • Cheater Dolly Assembly
    • Mainly used for roof bolting applications
    • Provides extra reach
  • Thread Wear Gauge
    • Tool to measure the gauge wear of the thread Spear
    • Tool used for rod retrieval Knock Off Block
    • Quick bit removal for collar and taper applications Gauge H22 Chuck
    • Chuck wear tool
  • Bit Gauge
    • Tool to measure the gauge wear of the bit

3rd Party Adapter Products: Shanks

To assure maximum compatibility for our customers, Boart Longyear provides 3rd party shank adapters for use with all major competitive manufacturers.

CANON

ATLAS COPCO

FURUKAWA

GARDNER DENVER

INGERSOL RAND

MONTABERT

TAMROCK

TOYO