What Is This Drill Bit and What Does It Do?

What exactly is the 30mm 2-wing PDC anchor bit, and where is it used?

A: This is a 30mm diameter, two-wing PDC drill bit purpose-built for anchor bolt hole preparation in underground excavation and surface ground-support projects. It drills the hole into rock before a rock bolt is inserted and grouted. The 30mm size is typically specified in narrow-heading tunnels, underground mine roadways with tight bolt spacing, and precision anchoring applications where hole diameter must be minimized to preserve surrounding rock integrity. Common deployment includes coal and hard-rock mine roadway reinforcement, tunnel roof and sidewall support, slope stabilization, and foundation micropile installation.

PDC Cutters — The Core Technology

What type of PDC cutters does this bit use, and why 1304 half-round specifically?

A: This bit uses 1304 half-round PDC cutters — 13mm diameter, 4mm thick polycrystalline diamond compacts cut in half. At 30mm body diameter, full-round cutters create excessive cutting width relative to the blade face, causing high torque and premature cutter wear. The half-round geometry halves the contact area, distributing cutting force more efficiently across the small-diameter wing face. Two half cutters sit brazed into precision-machined pockets on each wing, providing four cutting edges total that maintain continuous bottom-hole coverage at this compact size.

                                                                                                                                                                                                                                            

What makes these PDC cutters "enhanced"?

A: "Enhanced" refers to the PDC cutter grade itself — higher abrasion resistance, thermal stability above 700°C, and greater impact toughness compared to standard PDC grades. Diamond surface hardness exceeds 80 HRc (premium grades reach 90+ HRc). The practical result is that the cutters retain a sharp working edge longer under continuous drilling, which at 30mm diameter translates directly into more holes drilled per bit before the cutters wear past their usable profile.

Are there trade-offs with the 1304 half-round cutter at 30mm?

A: The main trade-off is depth of cut per revolution. Half-round cutters at 30mm diameter have limited exposure height compared to full-round cutters on larger bits (42mm, 48mm). This means penetration per revolution is lower — but in the rock strength range where 30mm anchor bits operate (below f=10), the available thrust from handheld and light bolting rigs is also limited, so the cutter geometry and the machine capability are well-matched. In harder formations, stepping up to a 42mm or 48mm bit with full-round cutters provides more aggressive penetration if the rig can deliver sufficient thrust.

                                                                                                                                                                                                                                            

Connection and Compatibility

What thread does this bit use — is it for drill rods or anchor bolts?

A: The thread matches the rock bolt (anchor rod) specification used on your project, not a drill steel thread. Rotary percussive bits connect to hex or button-end drill steels; PDC anchor bits connect directly to the bolt rod that will remain in the hole. Thread form and pitch follow the bolt manufacturer's standard — commonly metric (e.g., M20, M24) or imperial thread patterns specified in your ground-support design. When ordering, provide the bolt thread specification and we will machine the connection to match.

Will this bit work on handheld pneumatic bolters?

A: Yes. The 30mm bit is light enough for handheld pneumatic roof bolters, electric anchor drills, and hydraulic bolting jumbos, as long as the spindle nose thread matches the bit connection. In narrow-heading development — typical in coal mine gate roads and small-diameter tunnels — handheld bolters are the most common tool for this bit size. For surface anchoring rigs with higher torque capacity, the bit performs well but may be underutilized compared to a larger 42mm or 48mm bit that the rig could handle.

                                                                                                                                                                                                                                            

Formation Suitability and Performance

What rock types and hardness range can this bit handle?

A: Effective in soft to medium-hard formations up to approximately Protodyakonov hardness f=8-10 (roughly UCS below 80-100 MPa). This covers shale, mudstone, sandstone, limestone, and soft granite — the dominant rock types encountered in underground mine roadways and tunnel headings. Where the formation exceeds f=10 consistently, carbide-button anchor bits or larger-diameter PDC bits with heavier cutter grades may be needed.

How does it compare to tungsten carbide anchor bits in real operations?

A: Documented underground operations in Australia, South Africa, and Eastern Europe report that PDC anchor bits last 10-30 times longer than carbide anchor bits in comparable rock and deliver 60%+ higher penetration rates. The multiplier varies with formation abrasivity — in quartz-bearing sandstone the PDC advantage is largest; in clean shale the advantage is smaller but still significant. Unlike carbide bits, PDC bits require no re-grinding, which eliminates a labor-intensive maintenance step on every shift.

                                                                                                                                                                                                                                            

Structural Components

What are the key structural parts of this bit?

A: The bit is a single-piece steel body with 1304 half-round PDC cutters brazed into precision pockets on each wing face. A center post at the crown maintains dimensional stability. Tungsten carbide alloy gauge segments protect the outer diameter from abrasion. Between the two wings, open flute channels provide chip clearance and fluid passage. At 30mm there are no backup cutters — the geometry does not accommodate them — and no nozzles; chip evacuation relies on the natural flow path through the flutes, which works well with the low-pressure water or air flush from handheld bolting units.

Why no backup cutters at 30mm?

A: Backup cutters sit behind primary cutters to protect the blade body when primary cutters wear down. At 30mm diameter, the blade face is too narrow to hold both a primary and a backup cutter in the same radial position. Gauge segments serve the equivalent function at the outer diameter — they protect the body steel once the primary cutters have worn to their gauge point. Backup cutters become feasible at 42mm and above.

                                                                                                                                                                                                                                            

Economics and Cost Efficiency

Where does the cost saving come from?

A: Three compounding factors. First, bit consumption: crews switching from carbide to PDC anchor bits report 80-90% fewer bit changes per shift in documented UK, Polish, and South African underground operations. Second, zero regrinding: carbide bits require periodic sharpening on a grinding wheel, consuming labor time and machine downtime that PDC bits eliminate entirely. Third, more bolts per shift: faster penetration per hole means higher bolt installation rates, which in development headings directly accelerates advance meters per shift. The combined effect typically reduces cost per bolt installed, even accounting for a higher unit price for the PDC bit.

Is this bit cost-effective at low drilling volumes?

A: Yes. Even for a single bolting machine running a handful of holes per day, the elimination of regrinding logistics and bit-change downtime simplifies tool management. The economics improve further in high-volume roadway development where hundreds of bolts are installed per shift and the per-meter savings compound across the entire heading advance.

                                                                                                                                                                                                                                            

Quality and Manufacturing

What standards does SUNGOOD apply in manufacturing this bit?

A: The bit body is machined from alloy steel selected for strength and machinability. The 1304 PDC cutters are brazed using a high-temperature vacuum or controlled-atmosphere process to ensure full metallurgical bonding without thermal damage to the diamond layer. Each production batch undergoes dimensional inspection and pull-out force testing on the cutter brazements. Custom dimensions and thread forms are available on request.

Can the bit dimensions or thread be customized?

A: Yes. SUNGOOD supplies custom sizes and connection specifications to match the anchor bolt standards used in your region or project. Contact yanceychang@zzsungood.com with your diameter requirement, thread specification, and formation type for a recommendation.

                                                                                                                                                                                                                                            

Related Products: 48mm 2 Wings PDC Anchor Bit Roof Bolter Drill Bit for Mining

Type:PDC ANCHOR BIT WITH HALF CUTTERS Two blades carry half-round PDC cutters (each blade has 1-2 half-cutters, total 2 cutting elements) brazed into machined slots on the blade faces.