In the world of hard rock drilling, the choice of tooling can make or break a project. Whether you are tunneling through granite, sinking a blast hole in an underground mine, or anchoring a slope in a quarry, the
thread button bit is one of the most widely used and reliable
rock drilling tool options on the market. With its threaded connection system and tungsten carbide buttons, it delivers the penetration rate, durability, and hole straightness that professionals demand.
But with multiple thread sizes, face designs, and button configurations available, selecting the right bit is not always straightforward. This guide walks you through everything you need to know about thread button bits — from how they work to how to choose the best model for your specific drilling conditions.
What Is a Thread Button Bit?
A thread button bit is a percussive drilling tool used in top-hammer drilling systems. It features a threaded shank that screws onto a drill rod or shank adapter, and a face studded with spherical tungsten carbide buttons. When the rock drill delivers percussive energy through the rod to the bit, these buttons crush and chip away the rock, creating a clean, straight hole.
Compared to tapered bits, thread button bits offer a more secure connection, better energy transfer, and the ability to drill deeper and straighter holes. They are the go-to choice for long-hole drilling applications in mining, tunneling, and construction — where hole depth, precision, and bit life are critical.
Common Thread Sizes and Their Applications
Thread button bits come in a range of standardized thread profiles, each suited to different drilling rig sizes and rock conditions. The table below summarizes the most common sizes:
| Thread Size |
Typical Bit Diameter |
Best For |
| R25 |
45 mm – 65 mm |
Small-scale mining, benching, light tunneling |
| R32 |
51 mm – 76 mm |
General mining, drifting, bolting |
| R38 |
64 mm – 89 mm |
Medium to hard rock drifting, production drilling |
| T38 |
64 mm – 89 mm |
Heavy-duty drifting, tunneling, hard rock mining |
| T45 |
76 mm – 102 mm |
Deep hole production drilling, quarrying |
| T51 |
89 mm – 127 mm |
Large-diameter production drilling, open-pit mining |
Choosing the correct thread size depends on your drill rig''s power output, the rod diameter, and the rock formation you are working in. A mismatch can lead to premature bit failure, poor energy transfer, or rod breakage.
Face Designs: Flat Face vs. ｄｒｏｐ Center vs. Retrac
The face profile of a thread button bit directly affects flushing efficiency, penetration rate, and hole quality. The three most common face designs are:
Flat Face Bits — All buttons sit on a flat plane. These bits offer excellent hole straightness and are ideal for collaring and precise drilling. TY Drill Bits offers flat face designs such as the
Flat Face R32-64mm Retrac Type Button Drill Bit for applications where accuracy is paramount.
ｄｒｏｐ Center Bits — The center of the face is slightly recessed, creating a pilot effect that improves centering and reduces hole deviation. The
ｄｒｏｐ Center T51-115mm Retrac Button Bit is a popular choice for deep hole drilling where straightness matters.
Retrac (Retractable) Bits — These bits feature a reverse taper or additional gauge buttons on the sides, allowing the bit to be pulled back through loose or fractured ground without getting stuck. The
76mm Retrac T38 Bit and the
R25-48mm Retrac Button Drill Bit are designed for challenging ground conditions where borehole stability is a concern.
Button Configuration: More Isn''t Always Better
The number, size, and arrangement of tungsten carbide buttons on the bit face determine how effectively it penetrates different rock types. Key considerations include:
Fewer, larger buttons (e.g., 5–7 buttons) — Better for soft to medium rock. They deliver more impact energy per button, resulting in faster penetration. The
R32-51mm 7 Buttons Thread Rock Drill Bit is well-suited for medium-hard formations.
More, smaller buttons (e.g., 9–12 buttons) — Better for hard and abrasive rock. They distribute wear more evenly and maintain penetration rate over the bit''s service life.
Peripheral (gauge) buttons — These are critical for maintaining hole diameter. Retrac designs feature extra gauge buttons on the side of the bit body to protect against jamming during rod withdrawal.
Thread Button Bits in Mining and Tunneling
Thread button bits are indispensable in both underground and surface mining operations. In underground drifting and tunneling, they are used with hydraulic jumbos to drill blast holes — often in tough, abrasive formations. The
T51 Retrac Rock Button Bit for Ore Mining is specifically engineered for large-diameter production drilling in open-pit and underground mines, where high penetration rates and long service life are non-negotiable.
In quarrying and construction, thread button bits are paired with
DTH drilling tools or top-hammer rigs for bench drilling, foundation anchoring, and slope stabilization. The ability to drill deep, straight holes in fractured rock makes them a versatile choice across multiple industries.
How to Choose the Right Thread Button Bit
Selecting the optimal thread button bit involves evaluating five key factors:
1. Rock hardness and abrasiveness — Harder rock requires smaller, more numerous buttons and a tougher carbide grade. Softer rock benefits from fewer, larger buttons for faster penetration.
2. Hole diameter and depth — Larger diameters generally require larger thread sizes (T45, T51) to handle the increased torque and impact energy.
3. Drill rig specifications — Match the thread size and bit diameter to your rig''s power class. Hydraulic jumbos typically use R32–T38, while production drills use T45–T51.
4. Ground conditions — In fractured or loose formations, a retrac design is essential to prevent stuck bits and lost holes.
5. Flushing requirements — Ensure adequate flushing hole size and placement to clear cuttings efficiently, especially in deep holes.
Why Source Thread Button Bits from TY Drill Bits?
Xi''an Heaven Abundant Mining Equipment CO.,LTD (TY Drill Bits) has been manufacturing and supplying
rock drilling tools since 2010. Based in Xi''an, Shaanxi, China, the company provides a full range of thread button bits in sizes R25, R32, T38, T45, and T51 — covering diameters from 45 mm to 127 mm.
Key advantages of working with TY Drill Bits:
• ISO9001-certified manufacturing with quality control at every stage
• Export-focused: 91%–100% of products shipped to international markets
• OEM services available for custom bit designs and private labeling
• Competitive FOB, CFR, CIF pricing with flexible payment terms including L/C, T/T, and PayPal
• Lead time within 15 working days for both peak and off-season orders
• Expertise across the full drilling tool spectrum, from PDC bits and tricone bits to DTH hammers and core bits
With 14 thread button bit models in stock and the ability to customize based on your formation requirements, TY Drill Bits offers a one-stop solution for mining companies, drilling contractors, and equipment distributors worldwide.
Ready to Find the Right Thread Button Bit for Your Project?
Whether you need a single
thread button bit for a trial or a bulk order for a major mining operation, TY Drill Bits has the inventory and manufacturing capability to meet your requirements. Browse the full
rock drilling tool catalog, or contact the sales team directly for a quote tailored to your drilling conditions and budget.
Contact: Lucy@tydrillbits.com | Tel: 029-88894370 | Mobile: +86 15389082037
Xi'an Heaven Abundant Mining Equipment CO.,LTD
