Rock drilling is the backbone of mining, quarrying, tunneling, and construction projects. Whether you are drilling blast holes in an open-pit mine, anchoring in a tunnel, or opening a blast furnace tap hole, the
thread button bit at the end of your drill string is the single most critical component that determines your penetration rate, hole straightness, and overall drilling cost per meter.
Choosing the wrong bit can lead to premature wear, hole deviation, and unnecessary downtime. Choosing the right one can dramatically improve your productivity. In this guide, we break down thread types, face designs, selection criteria, and why sourcing from a reliable manufacturer matters.
What Is a Thread Button Bit?
A thread button bit is a type of
rock drilling tool designed for top-hammer drilling applications. Unlike tapered bits that are pressed onto a tapered rod, thread button bits screw directly onto threaded extension rods, providing a secure mechanical connection capable of transmitting high-impact energy from the rock drill into the rock face. The bit face is studded with tungsten carbide buttons that crush, fracture, and cut through rock formations under repeated percussive blows.
These bits are widely used in underground mining, surface mining, quarrying, tunnel construction, and blast furnace tapping. They are available in several thread profiles — R25, R32, R38, T38, T45, and T51 — each engineered for specific hole diameters and rock conditions.
Thread Types and Their Applications
Selecting the correct thread size is the foundation of effective drilling. The table below summarizes the most common thread profiles and their recommended applications.
| Thread Type |
Hole Diameter Range |
Best For |
| R25 |
38mm – 51mm |
Light-duty drilling, small-scale mining, anchoring, secondary breaking |
| R32 |
45mm – 76mm |
Versatile general-purpose drilling, underground mining, tunneling, quarrying |
| T38 |
64mm – 89mm |
Medium to heavy-duty drilling, hard rock, deeper holes |
| T45 |
76mm – 102mm |
Heavy-duty mining, large-diameter blast holes, hard abrasive formations |
| T51 |
89mm – 127mm |
Deep hole drilling, large-scale mining, toughest rock conditions |
R25 — Light-Duty Champion
R25 thread button bits are designed for small-diameter drilling in soft to medium-hard formations. They are lightweight, cost-effective, and ideal for handheld rock drills used in secondary breaking, scaling, and light anchoring work.
R32 — The Industry Workhorse
R32 is arguably the most popular thread standard in the industry. It offers an excellent balance of strength, versatility, and cost-effectiveness. R32 bits perform reliably in medium to hard rock conditions and are the go-to choice for most underground mining and general quarrying operations.
T38 — Stepping Up for Harder Rock
With a larger thread cross-section, T38 bits transmit greater torque and impact energy. They are designed for harder rock conditions and deeper holes where R32 would be pushed beyond its limits. T38 bits are commonly used in production drilling and bench blasting.
T45 and T51 — Heavy-Duty Deep Hole Drilling
For the most demanding applications — deep production holes in hard abrasive formations, large-scale open-pit mining, and serious quarrying — T45 and T51 thread button bits deliver the highest impact energy transmission. T51 bits in particular are built for extreme conditions where nothing less will do.
Face Designs: Flat Face vs. ｄｒｏｐ Center (Retrac)
Thread button bits come in two primary face designs, each with distinct advantages depending on the drilling conditions.
Flat Face Bits
The standard design for most general drilling applications. The flat profile provides stable drilling with good hole straightness. Flat face bits work well in competent, medium-hard rock where hole deviation is not a major concern. They are the most economical choice for straightforward drilling conditions.
ｄｒｏｐ Center (Retrac) Bits
Retrac bits feature a recessed center with angled outer buttons that create a self-centering effect. This design excels in fractured or faulted rock where hole deviation is a serious risk. The retrac geometry also helps pull the bit back smoothly during rod changes, reducing the chance of jamming. For challenging ground conditions, the additional cost of a retrac bit is quickly offset by reduced downtime and straighter holes.
Five Key Factors for Selecting the Right Thread Button Bit
1. Rock Formation Hardness
This is the single most important factor. Soft formations require bits with fewer, more aggressive buttons spaced farther apart for maximum penetration. Hard formations demand more buttons, closer spacing, and wear-resistant carbide grades. Using a bit designed for soft rock in hard granite will destroy the buttons in minutes. Using a hard-rock bit in soft shale will result in slow penetration and wasted energy.
2. Hole Diameter and Depth
Hole diameter dictates your minimum thread size. As a general rule, larger holes require larger threads. Depth also matters — deeper holes generate more stress on the threaded connection. Even if a smaller thread technically fits the diameter, upgrading to the next size may be necessary for deeper holes to prevent connection failures.
3. Drilling Rig Specifications
Your rig's impact power, rotation speed, and feed force must be matched to the bit. A bit that is too large will overwhelm the rig, causing poor penetration and premature wear. A bit that is too small underutilizes the rig's capability. Always consult your rig manufacturer's specifications when selecting bits.
4. Flushing Medium and Requirements
Effective flushing clears rock cuttings from the hole and cools the bit face. Most thread button bits use center flushing with compressed air or water. In sticky or wet formations, larger flushing holes or side grooves may be needed. Poor flushing is a leading cause of premature bit failure.
5. Button Shape and Configuration
Button shapes — spherical, ballistic, or conical — affect penetration rate and wear resistance. Spherical buttons offer the best wear resistance for hard rock. Ballistic buttons provide faster penetration in softer formations. The number and arrangement of buttons on the bit face also influence drilling performance and should be matched to the rock type.
Why Source Your Thread Button Bits from TY Drill Bits?
Xi'an Heaven Abundant Mining Equipment CO.,LTD — operating as TY Drill Bits — has been a trusted manufacturer and supplier of drilling tools since 2010. Based in Xi'an, China, we export 91–100% of our production to customers worldwide. Here is what makes us the right partner for your drilling consumable needs:
Comprehensive Thread Button Bit Range
We manufacture thread button bits in R25, R32, T38, T45, and T51 profiles, covering diameters from 38mm to 127mm. Our catalog includes both flat face and retrac (ｄｒｏｐ center) designs, with options for 7-button, 9-button, and custom configurations to match your specific rock conditions.
ISO9001 Certified Quality
Every bit we produce undergoes rigorous quality control from raw material inspection to final dimensional checks. Our ISO9001 certification ensures consistent manufacturing standards that you can rely on, batch after batch.
OEM Services and Customization
We provide full OEM manufacturing services. Whether you need custom button configurations, specific carbide grades, or your own branding and packaging, we can accommodate your requirements.
One-Stop Sourcing for All Rock Drilling Tools
Beyond thread button bits, we supply a complete range of drilling consumables:
DTH drilling tools including hammers and bits for down-the-hole applications,
PDC drill bits for water well and mining drilling,
tricone bits for oil and hard formation drilling, plus core bits, drill rods, shank adapters, and cutting tools. One supplier, one relationship, all your drilling needs covered.
Competitive Pricing and Fast Delivery
Factory-direct pricing with no middleman markup. We support flexible payment terms including L/C, T/T, PayPal, and Western ｕｎｉｏｎ. Our standard lead time is within 15 working days, and we maintain stock of popular sizes for even faster turnaround. We ship under FOB, CFR, CIF, EXW, and other common Incoterms to suit your logistics preferences.
Make the Right Choice for Your Next Drilling Project
Selecting the right thread button bit is not just about picking a diameter — it is about matching the thread type, face design, button configuration, and carbide grade to your specific rock formation and drilling equipment. A well-chosen bit delivers faster penetration, longer service life, and lower total drilling cost per meter. A poorly chosen bit does the opposite.
Whether you need standard R32 bits for everyday quarrying or heavy-duty T51 retrac bits for deep hole mining in hard granite, TY Drill Bits has the product and the expertise to support your operation.
Ready to Get the Right Thread Button Bits for Your Project?
Contact our team today for expert advice, technical specifications, and a competitive quotation. Send your inquiry to
Lucy@tydrillbits.com or reach us on
WhatsApp at +86 15389082037. Visit our website at
www.tydrillingbit.com to browse our full product catalog. Let us help you drill smarter, faster, and more cost-effectively.
Xi'an Heaven Abundant Mining Equipment CO.,LTD
