Rock Drill Button Bits 2026: DTH vs Top Hammer Selection Guide
Button Bit for Rock Drilling: The Complete Selection Guide
A button bit is a rock drilling tool featuring multiple tungsten carbide inserts—called "buttons"—mounted on a steel body. Unlike chisel bits or cross bits that cut rock along a line, button bits fracture rock through a crushing mechanism: each button concentrates percussive energy into a small contact point, creating micro-fractures that allow efficient penetration. MSD is a China-based rock drilling tools manufacturer with 23+ years of experience producing button bits for mining, quarrying, water well, and construction applications.
Button bits work with top hammer drilling rigs. The rock drill transmits impact energy through the drill string to the bit face, while the buttons crush the rock. Compressed air flows through flushing holes to clear cuttings from the hole bottom.
This guide covers everything you need to select the right button bit: button shape, face design, body type, and thread compatibility—matched to your specific rock conditions and equipment.
Button Bit vs Other Rock Drill Bits
Before selecting a button bit, understand how it compares to alternatives. The right choice depends on formation hardness:
| Bit Type | Best For | Rock Hardness | Advantages | Limitations |
|---|---|---|---|---|
| Button Bit | Hard, abrasive rock | Medium to Very Hard (f=8–18+) | Longest life, regrindable, highest penetration in hard rock | Higher initial cost |
| Cross Bit | Softer rock, cost-sensitive | Soft to Medium (f=3–8) | Lower cost, simple design | Wears faster in hard rock |
| Chisel Bit | Very soft rock | Soft (f=2–5) | Lowest cost | Not suitable for hard rock |
Decision Rule: If your formation hardness exceeds f=8 (granite, basalt, quartzite, gneiss), button bits are the optimal choice. For softer limestone, sandstone, or shale below f=6, cross bits may offer sufficient performance at lower cost.
Types of Button Bits by Button Shape
The button shape determines the balance between penetration rate and wear resistance. Matching the right shape to your rock formation is the single most important selection decision.
Spherical (Domed) Buttons: Rounded, dome-shaped profile that distributes impact force over a larger contact area. Maximum wear resistance in extremely hard, highly abrasive rock (granite f=14–18, quartzite, taconite). The rounded shape resists chipping and breakage under extreme forces and maintains its profile longer than aggressive shapes.
Ballistic (Parabolic) Buttons: Sharp, pointed profile that concentrates force into a smaller contact area. Fastest penetration in soft to medium rock (limestone, shale, dolomite, f<10). The aggressive tip achieves rapid initial penetration but wears faster in highly abrasive conditions.
Conical (Tapered) Buttons: A tapered point profile that sits between spherical and ballistic. Balanced penetration speed and wear resistance for medium to hard rock (f=10–16). The versatile default choice when rock conditions are variable or uncertain.
Button Shape Selection Matrix:
| Rock Type | Hardness (f-value) | Abrasiveness | Recommended Shape |
|---|---|---|---|
| Granite | f=14–18 | High | Spherical |
| Basalt | f=10–16 | Medium-High | Spherical |
| Quartzite | f=16–20 | Very High | Spherical |
| Gneiss | f=10–15 | Medium | Conical |
| Dolomite | f=6–10 | Low-Medium | Ballistic or Conical |
| Limestone (hard) | f=4–8 | Low | Ballistic |
| Shale | f=2–4 | Low | Ballistic |
> Rule of Thumb: Soft rock (f<8) ballistic="" buttons="" for="" maximum="" speed.="" hard="" rock="" f="">14) → Spherical buttons for maximum durability. When in doubt → Conical for balanced performance.
Types of Button Bits by Face Design
The face design controls energy distribution, flushing efficiency, and hole straightness. Four designs serve different rock conditions:
| Face Design | Energy Distribution | Best For | Trade-off |
|---|---|---|---|
| Flat Face | Even across entire face | Mixed or unknown formations, very hard rock | Maximum durability and hole straightness; moderate penetration speed |
| Concave Face | Concentrated at center | Soft to medium rock (f<10): clay, shale, limestone | Fastest penetration rate; lower wear resistance |
| Convex Face (Dome) | Concentrated at gauge | Hard, abrasive rock (f>14): granite, quartzite | Highest gauge protection and wear resistance; slower penetration |
| Drop Center | Hybrid: aggressive center + protected gauge | Variable formations, production drilling | Good balance of speed and gauge life; medium-fast penetration |
> Rule of Thumb: Soft rock (f<8) concave="" for="" speed.="" medium="" rock="" f="" flat="" versatility.="" hard="">14) → Convex for gauge protection.
Standard vs Retrac Body Design
The bit body design affects retrieval ease and performance in fractured ground.
Standard (Normal) Body: Straight skirt with no rear cutting elements. Best for stable, competent rock formations. Lower cost. The default choice for general-purpose drilling.
Retrac (Retractable) Body: Features a tapered skirt with cutting grooves on the rear. Designed specifically for fractured, fissured, or collapsed rock. The rear cutting elements allow the bit to drill itself out if rock falls behind it during retraction, dramatically reducing stuck bit incidents.
In a Canadian quarry project drilling heavily fractured granite, switching from standard to Retrac body bits reduced stuck drill string incidents by over 90%—from 2–3 per week to nearly zero. This eliminated costly fishing operations and improved crew safety.
Read the full quarry case study →
Thread Types and Compatibility
Button bits connect to drill rods via threaded shanks. Matching the correct thread type to your drilling equipment is essential—mismatched threads cause joint failure and potential downhole tool loss.
| Thread | Bit Diameter Range | Typical Applications |
|---|---|---|
| R25 / R28 | 33–45 mm | Tunneling, drifting, rock bolting |
| R32 | 43–76 mm | General mining, quarrying, [construction](https://www.rock-drillbits.com/applications/construction) |
| T38 | 64–89 mm | Bench drilling, production drilling |
| T45 | 70–115 mm | Heavy bench drilling, long hole |
| T51 | 89–115 mm | Large hole production drilling |
| ST58 | 89–102 mm | Heavy-duty underground, long hole |
| ST60 | 92–140 mm | Large-scale surface mining |
| ST68 | 102–152 mm | Maximum diameter top hammer drilling |
MSD manufactures thread button bits in all thread types listed above, with diameters from 33 mm to 152 mm. All bits are compatible with equipment from major manufacturers including Epiroc/Atlas Copco, Sandvik, and Furukawa.
Common Mistakes in Button Bit Selection
Avoiding these errors prevents premature wear, wasted budget, and downhole problems:
1. Using ballistic buttons in highly abrasive hard rock. Ballistic buttons penetrate fast but wear out rapidly in granite or quartzite (f>14). The aggressive tip profile erodes within hours. Switch to spherical buttons—they penetrate slower initially but drill far more total meters.
2. Ignoring face design for the rock condition. A concave face bit in very hard abrasive rock loses gauge buttons quickly because energy concentrates at the center, leaving the gauge under-protected. Use flat or convex face in hard rock.
3. Using standard body bits in fractured ground. Standard body bits have no rear cutting capability. In fractured or fissured rock, collapsed material traps the bit during retraction. Retrac body bits solve this at only 10–20% cost premium.
4. Mismatching thread types. A T38 bit on a T45 rod does not fit. Verify your shank adapter and rod thread specification before ordering.
5. Skipping regrinding. Button bits are designed to be reground 3–5 times. When button protrusion reduces by 30–40%, regrind rather than replace. This can double or triple total bit life and dramatically reduce cost per meter.
How to Select the Right Button Bit: 5-Step Framework
Step 1 — Identify Rock Conditions: Assess hardness (f-value) and abrasiveness. If unknown, send a rock sample for testing or start with the most conservative choice (spherical buttons, flat face).
Step 2 — Choose Button Shape: f<8 ballistic.="" f="" conical.="">14 → Spherical.
Step 3 — Choose Face Design: Soft rock → Concave. Medium → Flat. Hard → Convex. Variable → Drop Center.
Step 4 — Determine Body Type: Stable formation → Standard body. Fractured or fissured rock → Retrac body.
Step 5 — Match Thread and Diameter: Check your drill rig's thread specification. Select bit diameter based on your hole requirement (typically 64–115 mm for bench drilling, 33–51 mm for tunneling and bolting).
Proven Field Performance
Australian Marble Quarry: MSD T51-115 mm thread button bits with spherical buttons and flat face design were deployed in medium-hard marble (f=8–10). Result: 25% faster drilling speed and 30% longer bit life compared to the previous supplier's equivalent specification. The quarry subsequently standardized on MSD for all top hammer consumables.
Read the full Australia case study →
Get the Right Button Bit for Your Project
Proper button bit selection—matching button shape, face design, body type, and thread to your specific rock conditions—maximizes drilling efficiency and minimizes cost per meter.
Need help selecting? Contact MSD engineers with your rock type, drill rig model, and hole diameter requirements. We will recommend the optimal button bit configuration for your application.
Frequently Asked Questions
What are button bits used for?
Button bits are used for drilling holes in hard rock formations with top hammer drilling rigs. Common applications include blast hole drilling in mining and quarrying, anchor and rock bolt installation, tunneling, and geotechnical investigation. Button bits are specifically designed for medium-hard to very hard rock types (f=8 and above) such as granite, basalt, gneiss, and quartzite.
What is the best drill bit for hard rock?
For hard rock (f>14) with top hammer rigs, button bits with spherical tungsten carbide inserts and flat or convex face design deliver the best combination of penetration rate and service life. Spherical buttons resist chipping in abrasive conditions, while flat or convex faces protect gauge buttons from premature wear.
What is the difference between spherical, ballistic, and conical button bits?
Spherical (domed) buttons have a rounded profile for maximum wear resistance in hard, abrasive rock. Ballistic (parabolic) buttons have a pointed profile for fastest penetration in soft to medium rock. Conical (tapered) buttons offer a balanced compromise—moderate penetration speed with good wear resistance—making them the versatile choice when rock conditions are variable or unknown.
How long do button bits last?
Button bit life depends on rock hardness, carbide grade, and regrinding practice. In typical hard rock conditions (f=10–16), a quality button bit with premium YK05 tungsten carbide drills 150–500 meters before requiring regrinding. With 3–5 regrinding cycles, total bit life can reach 500–2,000 meters. MSD button bits feature sub-0.1% body breakage rate and sub-0.5% button fallout rate (MSD factory data).
What thread type do I need for my button bit?
Thread type must match your drill rig and drill rod specification. The most common systems are R32 for general mining and construction (43–76 mm holes), T38 for bench drilling (64–89 mm), and T45/T51 for heavy production (70–127 mm). Verify your shank adapter thread before ordering. MSD manufactures button bits in all standard thread types from R25 through ST68.
*Technical content reviewed by MSD Engineering Team. | MSD — 23+ years of rock drilling tools manufacturing expertise | ISO 9001 Certified | Trusted by 1000+ drilling contractors in 40+ countries*
Technical content reviewed by MSD Engineering Team. | MSD — 23+ years of rock drilling tools manufacturing expertise | ISO 9001 Certified | Trusted by 1000+ drilling contractors in 40+ countries