Choosing Drill Steel and Rock Drill Bits

Selecting Drill Steel and Rock Drill Bits

If you need assistance in selecting a Rock Drill, you're in the right place.

With competitive pricing and prompt delivery, KSQ Technology aspires to be your preferred supplier and partner.

Step 1: Identify the Shank Configuration of Your Drill

The initial step in selecting the appropriate steel and bits for your rock drill and specific application is to identify the shank configuration on your drill.

The smallest common pneumatic drills are a variation of the CP9 design, utilizing a one-piece bit/drill steel combination known as a Whirly Bit.

When transitioning to larger handheld drills, you will encounter three prevalent shank sizes: 7/8 x 3 ⅛, 7/8 x 4 ⅛, and 1 x 4 ⅛. These dimensions represent the diameter of the hex steel (measured across the flats) and the length extending above the retaining collar. Larger sinker drills typically employ more substantial steel, but it is not unusual for a 55 lb drill to be configured for a 7/8 x 3 ⅛ shank. Knowing your drill’s shank configuration is vital before ordering steel.

Step 2: Establish the Drill and Bit Configuration for Your Rock Drill Shank

These bits combine both the bit and drill steel into one unit. The shank that fits into the drill, the body of the steel, and a silver brazed carbide tip make up this component. The body of the drill steel is slightly smaller than the bit to facilitate the upward movement of cuttings from the hole. Even a 1” shanked 60 lb class drill can bore a hole smaller than 1” to a limited depth.

Advantages

• Pneumatic drills can quickly create small holes, typically ranging from 5/8” to 1” in diameter with depths of up to 26”, though various sizes may be available.

Disadvantages

• These tend to be more expensive compared to separate steel and bits.
• The diameter of the steel decreases alongside the bit size, consequently reducing potential column strength. As a result, they are not suitable for off-line drilling, particularly with larger drills.
• Tips are non-replaceable; thus, when the bit wears out, the entire steel must be retired.

The details concerning the thread dimensions are essential for compatibility:

H thread is arguably the most widely utilized contractor thread owing to its versatility and availability. The male thread on the steel measures approximately 1” in diameter and is about 3/4” in length. Typically, the steel is stocked in lengths ranging from 12' to 120' across all three shank configurations. The bits are available from 1 3/8" up to 3" in full carbide cross (most common), with sizes from 1 3/8" to 2" in shallow carbide cross, 1 3/8" to 2 1/4" in button bits, and 1 3/8" to 2-5/8" diameter in all steel bits.

H thread drill steel is commonly crafted from high carbon steel that undergoes forging, machining, and heat treatment to ensure a wear-resistant outer shell while retaining a slightly softer core for efficient impact energy management and transfer. As shoulder drive steel, the skirt of the bit secures tightly around the forged/machined shoulder on the steel. The percussive energy is communicated through the steel and skirt of the bit to the face, fracturing the material directly in front.

Although H thread steel is predominant in contractor use, it possesses certain vulnerabilities. The shoulder drive requires the bit to remain secure against the steel's shoulder; if it loosens, the drilling forces are directed at the smaller threads on the bit and steel, which can lead to quick failure. Maintaining constant down pressure without allowing the drill to bounce should ensure effective operation in most hard rock drilling scenarios.

This bit is equipped with four sizable silver brazed carbide inserts, which perform exceptionally well in high-production hard rock drilling. They retain their profile admirably and can be sharpened if they lose effectiveness.

The economy bit is somewhat less expensive than the Full Carbide bit, but with fewer tungsten carbide inserts, they may sometimes prove to be more economical in specific situations, such as small jobs or in highly abrasive conditions prone to bit failures.

The button bit is slightly pricier than the Full Carbide cross bit, featuring multiple carbide buttons embedded in the bit's face. While they may appear dull initially, it is essential to understand how a percussive rock drill operates. Larger hand drills can generate sufficient impact energy to make these bits far more effective than cross bits in terms of speed and longevity under the appropriate conditions.

These cross bits, forged and hardened, offer the most cost-effective option; however, without the carbide component, one should expect a relatively brief lifespan, particularly in abrasive scenarios.

Tapered drill steel is traditionally utilized in underground mining with jackleg drills. The 12-degree taper is predominant in Canada, while the 11-degree variant is favored in the US and Central America. The female tapered bit is pushed onto the male tapered drill steel, and they can be separated using a bit knocker once the bit is worn out.

Some contractors favor this system as the steel is produced in greater volumes and is easier to manufacture, potentially leading to lower costs. However, it was originally intended for production mining, thus limiting its adaptability. The standard shank configuration for this steel is 7/8 x 4 ⅛, while the bits available are restricted. Crowder Supply offers shallow cross bits from 1" to 2", button bits at 1 3/8" and 1 1/2", and 11-degree steel in 18" through 12" increments. A failure to sustain steady down pressure may result in the bit becoming lodged in the hole.

Rope Thread Steel and Bits:

If you'd like to learn more about Tapered Rock Drilling Tools, feel free to contact us today for an expert consultation!

The 100 rope (1" rope, R25) and 125 rope (1 ⅛" rope, R32) are widely used in underground production mining tasks. Many contractors have opted for this steel type to achieve greater longevity, particularly in challenging conditions or when consistently drilling holes larger than 2 ½" in diameter. Typically, the drill steel is carburized, a method that infuses the steel with carbon elements in a furnace, providing an extremely hard outer layer while retaining a softer core to manage shockwaves from impacts. The threads are larger and longer, enabling them to bottom out within the rock bit, making this combination more forgiving under tough drilling conditions. Crowder Supply manufactures a broad range of steel and bit adapters for larger track drills, although it's often unnecessary to exceed these two thread types with handheld drills.

Rope thread steels also enable the use of drill strings by incorporating extension steels, allowing operators to drill deeper or longer holes in confined spaces.

Should you need assistance in making your selection, please don't hesitate to reach us at 888-883-.

The range of taper bits mainly consists of horseshoe chisel bits, tapered chisel bits, and cross bits. The horseshoe and tapered chisel bits are primarily designed for small and short holes, while cross bits are intended for drilling long holes in tough and cracked rock conditions. Tapered blade bits find their primary applications in mining, quarrying, tunneling, and anchoring.

>> Characteristics

The tapered button bit intended for small holes distinguishes itself from the threaded button bit by utilizing a taper match bit connected with the rod to be used in air leg or handheld jackhammer drilling for quarrying and mining.

>> Connect Shank Size: Φ19, Φ22, Φ25 at maximum

>> Bit Diameter: 32mm, 34mm, 36mm, 38mm, 40mm

>> Tapered Connection: 6 degrees, 7 degrees, 11 degrees, 12 degrees, etc.

>> Material: Alloy Steel Bar 45CrNiMoV, Tungsten Carbide Tips YK05 or T6, KK06, KK06H

>> Button Shape: Ballistic Face Type; Flat Face; Bit Body: Standard

>> Quantity of Buttons: 5, 7, 8 pieces

>> Primary Market: India, Saudi Arabia, Chile, South Africa, Peru

>> Specification

Raw Material: Alloy steel and tungsten carbides treated via cold pressing technique. Utilization: Coal Mining. Button Sizes: 32; 34; 36; 38; 40mm. Product Name: Taper Button Bit. Taper Angle: 7°/11°/12°. Diameter Range: 26mm-56mm. Skirt Lengths: 50-55mm; 60-70mm; 75mm-80mm. Lengths: 50mm~72mm. Socket Inside Diameter: 22/23/25mm. Advantages: High Performance. Button Type: ballistic, spherical button. Color: Request. Common Colors: Blue, Red, Yellow, Black, Green. Applications: Drilling and Construction. Packaging: Wooden cases or plastic boxes with 50 or 100 pieces. Transport: Air/Sea/Express. Custom Design: We can design according to client specifications and drawings, including button count, button type, and flushing holes.

>> Projects

For additional information on Rotary Drilling Tools, do not hesitate to reach out.